The effect of varying flock size on the development and subsequent laying performance of floor‐reared pullets

Light‐weight, hybrid pullets were reared on litter in flocks of 400, 800 and 1200 birds per pen. Floor space allowance was held constant at 0–093 m² per bird and other related factors of management were standardised. The different sizes of flock had no significant effect on growth rate or mortality, but individual food consumption was significantly higher in the 400‐bird flocks than in the larger units.

At 18 weeks of age, some of the birds from each treatment were transferred to battery cages and others to deep‐litter laying quarters and records of their performance in terms of egg numbers and size, food consumption, mortality and body weight gain were taken over a period of 1 year. The only consistently significant finding was that birds reared in groups of 1200 tended to produce larger eggs (as shown by market grading) and, when housed on deep litter, to eat more food than birds reared in the smaller flocks.     

The effect of varying stocking density on the development and subsequent laying performance of floor‐reared pullets

Light‐weight, hybrid pullets were reared on litter at 0.070, 0.093, 0.139 and 0.186 m² of floor area per bird. Flock size was constant at 400 birds per pen and other related factors of management were standardised. Results showed that the different densities of stocking had no commercially important effect on growth rate, food consumption or viability, but feathering was poorer in the more densely populated groups.

At 18 weeks of age, some of the birds from each treatment were transferred to battery cages and others to deep‐litter laying quarters and records of their performance in terms of egg production and quality, food consumption, mortality and body weight gain were taken over a period of one year. The use of high stocking densities during the preceding rearing stage caused no impairment of the performance of layers kept in batteries, but was possibly responsible for a small decline in productivity of layers housed on deep litter.     

Photorefractoriness in broiler breeders: sexual maturity and egg production evidence

1. Photorefractoriness was assessed in two lines of broiler breeders. In one trial, male-line and female-line pullets were reared on the floor and transferred to individual cages at 15 weeks. Birds were either maintained on 8-, 11- or 16-h photoperiods or transferred from 8- to 16-h photoperiods at 67 or 124 d. In the second trial, female-line pullets were concurrently housed in the same rearing facilities as trial 1 and transferred to adult floor-pens at 12 weeks. These birds were either maintained on 11- or 16-h photoperiods or transferred from 8- to 11-h or from 8- to 16-h photoperiods at 140 d. 2. In the cages, male-line and female-line birds responded similarly to the lighting treatments, but with the male-line maturing 1 to 2 weeks later than the female-line in each case. Birds on constant 11-h photoperiods matured 3 to 8 d earlier than constant 8-h birds, but 3 weeks earlier than constant 16-h birds. Birds photostimulated at 67 d matured at a similar time to constant 16-h birds, but almost 7 weeks later than those transferred from 8 to 16 h at 124 d. In the floor facilities, constant 11-h birds matured 3 weeks earlier than constant 16-h birds, but almost 2 weeks later than either of the photostimulated groups. Birds transferred from 8 to 16 h matured 4d earlier than those transferred from 8 to 11 h. 3. Caged birds maintained on 16 h or transferred from 8 to 16 h at 67 d laid at least 24 fewer eggs, and had more hens not laying at 58 weeks, than birds maintained on 11-h days or those transferred from 8 to 16 h at 124 d. In the floor-pens, constant 11-h and both photostimulated groups produced about 20 more eggs to 56 weeks of age than the constant 16-h controls. 4. Collectively, these findings indicate that conventionally managed broiler breeders exhibit photorefractoriness. Additionally, a combination of photorefractoriness and controlled feeding appears to prevent broiler breeders from being photoresponsive until at least 10 weeks of age, and to cause some individuals still to be photoperiodically non-responsive at 18 weeks.     

Effect of husbandry system on broken bones and bone strength in hens

The effects of rearing system, forced moulting and three different layer housing systems on broken bones and bone strength, were examined in hens at the end of lay. Weak bones and broken bones were more common in battery hens which had been reared to point of lay on deep litter rather than in cages. The incidence of old breaks was greater in perchery birds (14 per cent) than in tiered terrace birds (5 per cent), and there was also a difference between their incidence in two types of perchery design (17 per cent and 11 per cent). Moulting was associated with a transient decline in bone strength, followed by an increase in strength during the second lay.     

Effect of feeding low lysine starters and developers on growth,sexual maturity and subsequent performance of broiler breeder pullets 1

Pullets that were fed diets containing 0.53 per cent and 0.42 per cent lysine grew at a slower rate and matured later than those that were given adequate amount of lysine. The latter pullets converted their food more efficiently than did the restricted pullets with the exception of the group fed the ration containing 0.53 per cent lysine for the first 12 weeks. The restricted pullets consumed less food during the growing period. A smaller bird was produced on less food. The restricted pullets were also lighter than the control pullets at the end of the laying season. A saving in food costs is indicated because the smaller hen would require less food for maintenance.

There was a higher mortality in the pullets fed a ration containing 0.53 per cent lysine during the growing period. The mortality in the group fed the ration containing 0.42 per cent lysine from 7 to 22 weeks of age was the same as that of the control. There were no differences in mortality during the laying season that could be related to methods of rearing the pullets.

During the laying season, the highest rate of lay was obtained from hens which had been fed the ration containing 0.42 per cent lysine from 7 to 22 weeks of age. Hens fed on the ration containing 0.53 per cent lysine from o to 4, 8 or 12 weeks of age showed no improvement in rate of lay as compared with controls.

Hens fed the ration containing 0.42 per cent lysine from 7 to 22 weeks laid fewer small eggs at the beginning of the laying season than did hens receiving adequate amounts of lysine throughout or fed the ration containing 0.53 per cent lysine from o to 4, 8 or 12 weeks. The hens fed the latter ration laid smaller eggs throughout the laying season.

No differences were found between the fertility, hatchability or embryonic mortality of eggs obtained from hens fed on lysine deficient diets during growth and those fed on diets adequate in lysine.     

Effect of furnished small group housing systems and furnished cages on mortality and causes of death in two layer strains

1. Mortality and causes of death were recorded over two trials with 13045 Lohmann Selected Leghorn (LSL, white layer strain) and 4410 Lohmann Brown (LB) laying hens kept in furnished small group housing systems and furnished cages. In trial 1, hens were housed from weeks 19 to 71 (LSL) and 17 to 69 (LB). In trial 2, LSL hens were housed from weeks 18 to 57. 2. The hens were kept in groups of 40 and 60 in the furnished small group housing system Eurovent 625 + a-EU and in groups of 10 and 20 in the furnished cages Aviplus and Eurovent 625A-EU. 3. To investigate the possible effect on mortality of rearing the birds on litter floors or in cages, in trial 2 half of the LSL hens were reared on the floor and half in conventional cages. 4. Mortality was greater in the Eurovent furnished small group housing system (5.2%) than in the furnished cages Aviplus (4.0%) and Eurovent (4.2%). 5. Mortality was also affected by the interactions among housing system and trial, layer strain and rearing. In trial 1, more LB laying hens died in the Aviplus system than in the Eurovent group system. There was no significant difference in mortality of the LSL laying hens between housing systems in trial 1. In trial 2, mortality of the LSL hens was greater in the group housing system (hens reared on litter floors: 10.1%; hens reared in cages: 2.8%) than in the furnished cage Aviplus (hens reared on litter floors: 6.0%; hens reared in cages: 1.5%). 6. Mortality was greater in floor-reared LSL laying hens than in the LSL laying hens reared in conventional cages. 7. Group size within housing system had no significant effect on mortality. 8. The most common findings at autopsy were different types of cannibalism (65.51%), with vent cannibalism (38.57%) the most common.     

Cage size and flooring preferences in litter‐reared and cage‐reared hens

1. Pullets (Ross Rangers) reared commercially either in cages or on deep litter were tested for their responses to small (0.38 × 0.43 m) and large (0.76 x 0.86 m) cages with wire floors and to small and large cages with litter floors.

2. When tested at 29 weeks of age, the birds' responses were significantly affected both by cage size (large preferred to small) and by flooring (litter preferred to wire).

3. No difference in cage preference was apparent between cage‐reared and litter‐reared birds either when they were first tested at 17 weeks or when they were re‐tested at 29 weeks. Birds do not have to be reared on litter in order to be attracted by it.     

Rearing photoperiod and abrupt versus gradual photostimulation for egg-type pullets

1. Lohmann White and Lohmann Brown egg-type hybrids were reared on 6-, 8-, 10- or 12-h photoperiods, transferred to 12.5 h at 18 weeks and then given weekly increments to reach 14 h at 21 weeks. In a second experiment, Lohmann White pullets from the same rearing facility were transferred abruptly to 14 h at 18 weeks. 2. Body weight gain and feed intake to 6 and 18 weeks were positively correlated with rearing photoperiod in both breeds. Mortality to 18 weeks was unaffected. 3. Whether the photoperiod was increased abruptly or in a series of increments, Lohmann White pullets reared on 6 or 8 h matured 4 to 6 d later than pullets reared on 10 or 12 h. Rearing day-length had little effect on sexual maturity in Lohmann Brown pullets. 4. In both genotypes and each experiment, egg numbers, egg weight and shell strength increased with rearing photoperiod. Feed intake in the laying period was not significantly affected by rearing day-length, but a meta-analysis of all data showed a significant, though small, increase in adult feed intake with rearing photoperiod. Despite Lohmann White birds reared on 6 and 8 h having lower body weights throughout the laying period, they had larger body weight gains between 18 and 70 weeks than those reared on 10 or 12 h. There were no clear effects of rearing photoperiod on albumen height or mortality. 5. The heavier eggs and stronger shells of the birds reared on the longer day-lengths were correlated with heavier body weights at 18 weeks, and the superior egg numbers and higher feed intake were associated with age at sexual maturity.     

Limb bone strength and movement in laying hens from different housing systems

Walking and bouts of wing movement performed by 61-week-old ISA brown laying hens which had been taken from one batch of eggs and then kept in three different housing systems which allowed a gradation in spatial freedom, were recorded. After slaughter the breaking strengths of the humerus and tibia of birds from each system were measured. Birds from battery cages exhibited the fewest limb movements and had the weakest bones, their humeri having only 54 per cent of the strength of those of birds from a perchery. Birds from the Elson terrace system were heavier and had a stronger tibia than cage birds. Compared with perchery birds, terrace birds had weaker humeri and also performed fewer wing movements. The results indicate that the amount of movement possible for laying hens in battery cages was insufficient to avoid levels of osteopenia and consequent bone fragility much greater than in birds kept in the perchery and Elson terrace systems.     

Bone characteristics and body weight of broilers in different husbandry systems

1. An experiment was conducted to determine the effect of husbandry systems on bone characteristics and body weight. Broilers were reared in 5 different husbandry systems: wire mesh (WM) floored cages from 0 to 7 weeks; WM floored cages from 0 to 3 weeks and then transferred to floor pens; plastic mesh (PM) floored cages from 0 to 7 weeks; PM floored cages from 0 to 3 weeks and then transferred to floor pens; floor pens from 0 to 7 weeks.

2. Body weight at 3 weeks of age was affected by the husbandry systems, being greatest for the birds reared in floor pens. At 7 weeks of age, male broilers reared in PM floored cages had the lowest body weight and body weight gain from 4 to 7 weeks.

3. Humerus weight and ash content were affected by cage rearing whereas tibia weight and ash were not. Birds reared in PM cages had shorter tibia and humeri than birds reared in floor pens.     

The influence of graded levels of atmospheric ammonia on chickens. I. Effects on respiration and on the performance of broilers and replacement growing stock

Experiments have been carried out to study the influence of high concentrations of ammonia on the performance of chickens. One hundred parts per million by volume of ammonia caused reductions in the respiration rate of adult hens of between 7 and 24 per cent. Carbon dioxide production and respiratory depth were also reduced.

Broiler chickens reared in atmospheres containing high concentrations of ammonia from 28 days of age tended to eat less food than broilers reared in ammonia‐free atmospheres and at 100 p.p.m. of ammonia their growth rate was significantly reduced.

Replacement laying pullets reared in atmospheres containing ammonia from 11 to 18 weeks of age, ate less food than similar birds reared in ammonia‐free atmospheres. When the ammonia level was 78 p.p.m. by volume, food consumption was significantly reduced in the period from 15 to 30 weeks of age. This lowered food intake was associated with significantly less live‐weight gain up to 22 weeks of age, and pullets reared in atmospheres with high ammonia concentrations matured up to 2 weeks later than pullets reared in ammonia‐free atmospheres.     

A comparison of the shell strength of eggs from battery and deep‐litter units

The investigation involved 966 light‐hybrid pullets, 366 accommodated in battery cages and 600 kept on deep litter. Samples of their eggs were taken at four stages during the laying year for measurement of shell strength by the deformation technique. The results of these measurements were very similar for eggs produced under the two systems of housing.     

Influence of various nesting materials on nest site selection of the domestic hen

Nesting behaviour of LSL hens from a deep litter house and from a battery system was compared. Every hen was tested in one of two trial chambers containing a wire mesh floor and a nest unit with 5 nesting materials: wire mesh, perforated plastic, synthetic grass, wheat straw and oat husk. Wheat straw and oat husk were preferred as nesting materials to perforated plastic, synthetic grass and wire mesh. The results from these trials were confirmed in a deep litter house. After the nesting material, oat husk, was changed in two of 10 communal nests the hens did not accept those two nests for the trial period of two weeks and laid elsewhere. Hens of the same breed and age reared together on deep litter showed no differences in nest site selection and nesting behaviour regardless of whether they had previously been housed in a deep litter house or in cages.     

Changes in light intensity during the rearing period can influence egg production in domestic fowl

1. A total of 240 Shaver White and 240 ISA Brown pullets that had been reared in multi-bird cages on a 10-h photoperiod, and maintained at a light intensity of 3 or 25 lux, or changed from 3 to 25 lux or from 25 to 3 lux at 9 or 16 weeks of age, were moved into individual-bird cages at 20 weeks and transferred to 15-h photoperiods at 25 lux. 2. In both breeds, birds transferred from 3 to 25 lux at 16 or 20 weeks laid significantly more eggs than birds maintained on the brighter intensity from one day or increased to it at 9 weeks. 3. Mean egg weight, shell deformation, albumen height, feed intake and body weight gain in lay were not significantly affected by the light intensity treatments during the rearing period. There was, however, a small, but significant, negative correlation of egg numbers with mean egg weight, although this only partially explained the difference in egg numbers. The differences in egg production were unrelated to rate of sexual maturation.     

Pathogenicity of Listeria monocytogenes Scott A after oral and oculonasal challenges of day-old turkey poults

Listeria monocytogenes is a ubiquitous, environmental pathogen that has contaminated poultry ready-to-eat products resulting in large-scale recalls. Research is needed to determine the source of product and processing plant contamination with L. monocytogenes. The purpose of this study was to compare the oral and oculonasal routes of infection on the pathogenicity of L. monocytogenes in turkey poults under different housing conditions. One-day-old turkey poults were challenged by either route with the Scott A strain of L. monocytogenes and placed either in paper-lined battery-brooder cages for 1 wk or in floor pens on fresh pine-shaving litter. On day 7, birds challenged in battery cages were transferred to floor pens. Challenge by the oculonasal route resulted in higher mortality (P = 0.05) and lower body weights (P < 0.0001) compared with both nonchallenged controls and those challenged by the oral route. Birds contained in battery cages for 1 wk had higher mortality (P = 0.002) and higher body weights (P < 0.0001) compared with floor-pen-reared birds. Using direct plating, the challenge strain was isolated from the gall bladder, brain, and knee joint of only one dead poult challenged by the oculonasal route. These results suggest that day-old turkey poults may be more susceptible to an oculonasal challenge with L. monocytogenes than to an oral challenge and that containment in battery cages for the first week increased contact exposure to the challenge.     

A comparison of the effects of feeding treatments and lighting on age at first egg and subsequent laying performance and carcase composition of broiler breeder hens

The effects of the growth curve from 15 to 20 weeks, age at photostimulation and pattern of photostimulus on sexual maturity, egg production and egg weight were evaluated in two trials with broiler breeder females to 56 and 34 weeks of age (housed in litter pens and individually caged, respectively). Carcase composition and reproductive morphology of hens varying in laying efficiency were measured in the second trial. Trial 1: Four growth curves were applied from 15 to 20 weeks to pullets housed in litter pens. Birds were transferred from 8- to 10-h photoperiods at 20 or 24 weeks of age, followed by weekly increments of one hour to reach a 16-h final photoperiod. Lower-than-recommended body weights at 20 weeks significantly delayed sexual maturity, reduced peak rate of lay, total eggs and mean egg weight. However, double-yolked egg production was lower, resulting in non-significant differences in settable egg numbers between body weight treatments. Birds reared to the heaviest body weight exhibited a significantly advanced sexual maturity, but total egg numbers, peak rate of lay and mean egg weight were not significantly affected. However, the laying of more double-yolked eggs resulted in a decrease in the number of settable eggs. Delaying photostimulation to 24 weeks significantly retarded sexual maturity, reduced total and settable egg numbers, and increased mean egg weight. A tendency for fewer double-yolked eggs was observed. Trial 2: At 19 weeks, birds were selected from the 4 body weight categories in Trial 1 and moved to individual cages in 8 rooms. Five lighting programmes were applied. The pattern of photostimulation applied did not affect any of the production traits measured. At 34 weeks, 24 birds were selected for the analysis of reproductive morphology, presence of internal or multiple ovulations, and carcase composition. Eight hens showing an early age at first egg and regular egg production records, 8 birds showing erratic laying performance and 8 non-layers were killed for this purpose. There were no differences in carcase composition or reproductive morphology between these groups. No internal ovulations or double or multiple ovarian hierarchies were observed. The results presented confirm that broiler breeders do not require a lighting stimulus in order to initiate ovarian activity and that, where no lighting stimulus is given, body weight or feeding level plays a critical role in stimulating the birds to attain sexual maturity. However, when a lighting stimulus is given, factors such as body weight and body composition become relatively less important in regulating the age at sexual maturity.     

Effect of different types of litter material for rearing broilers

1. Coir dust was evaluated as broiler litter in comparison with sawdust and rice husk using 135 commercial broilers. Forty-five broiler chicks were reared to 42 d on a 50 mm layer of each of these litters. 2. Birds reared on coir dust showed no difference in food consumption, body weight gain, food conversion efficiency production number and survivability in comparison to those reared on saw dust and rice husk. 3. It was concluded that coir dust is suitable as broiler litter when cheaply available.     

Some husbandry factors affecting mortality and morbidity on a calf-rearing unit

The influence of some husbandry factors on morbidity and mortality was studied in 1996 artificially reared, dairy bred calves over the period from purchase until about six weeks of age. The effects of housing (indoors versus outdoors), penning (individual versus group), breed, time since purchase and season of purchase were examined. The overall mortality rate was approximately 4 per cent and calves were more likely to die if reared in groups outdoors than if reared either singly or in groups indoors. The mortality rate was significantly lower in calves purchased between April and June than at other times of year. Pneumonia was the most common disease symptom (48.3 per cent of calves) with diarrhoea the second most common (14.1 per cent). Neither the type of penning nor housing affected the incidence of pneumonia but diarrhoea was most common in individually penned calves. Case mortality rates for diarrhoeic calves in group pens were higher than for those in single pens and case mortality rates for pneumonia were highest for calves reared in groups outdoors. More than half the cases of pneumonia occurred between one and three weeks after purchase whereas two-thirds of the cases of diarrhoea occurred within the first week after purchase. However, case mortality rates for both conditions appeared to increase with time since purchase.     

笼养和地面平养对肉鸡生产性能的影响

分别于夏季采用7日龄AA肉鸡公雏264只,春季采用7日龄AA肉鸡和北京油鸡公雏各144只,分成2组,每组6个重复,进行地面平养和笼养生产性能比较试验,结果表明:夏季笼养AA肉鸡2～4周龄日增重低于地面平养(P<0.05),5周龄时高于地面平养(P<0.01);春季笼养AA肉鸡2周龄日增重、日采食量和体重高于地面平养(P<0.05);但笼养对AA肉鸡全期平均日采食量、平均日增重、试验末体重、饲料转化率、死亡率没有影响(P>0.05)。笼养北京油鸡表现为3～6周龄平均日采食量、体重高于地面平养(P<0.05),笼养对北京油鸡平均日增重、饲料转化率和死亡率没有影响(P>0.05)。     

Light intensity can influence plasma FSH and age at sexual maturity in domestic pullets

1. Shaver White and ISA Brown pullets were reared to 140 d in cage groups of 8 on a 10-h photoperiod of incandescent light and maintained at an illuminance of 3 or 25 lux, or transferred from 3 to 25 lux or from 25 to 3 lux at 63 or 112 d of age. 2. Plasma follicle stimulating hormone (FSH) concentration at 63 and 112 d was higher in both breeds for pullets maintained at an illuminance of 25 lux compared with 3 lux. After 2-4 d, and relative to constant-illuminance controls, plasma FSH increased significantly for ISA Brown transferred from 3 to 25 lux at 63 d and for Shaver White transferred at 112 d. Irrespective of genotype, plasma FSH for pullets given a decrease in illuminance at 63 or 112 d showed a tendency for less change than did constant-illuminance controls. 3. There was no significant difference in sexual maturity for ISA Brown maintained on 3 or 25 lux, but Shaver White pullets exposed to constant 3 lux matured later than those maintained on 25 lux. Shaver White matured later following an increase from 3 to 25 lux at 63 and 112 d, and earlier subsequent to a decrease from 25 to 3 lux at 112 d. ISA Brown pullets were not significantly affected by a change in illuminance at 63 or 112 d, though their responses were in the same direction as Shaver White. 4. Changes in plasma FSH in the 2- to 4-d period following a change in illuminance at 63 or 112 d were not significantly correlated with sexual maturity.