Effects of group size on the feeding behaviour and growth of chicks

1. The aim of the study was to see if social facilitation of feeding has a lasting effect on the growth of chicks.

2. In two experiments, newly hatched hybrid and Brown Leghorn chicks were reared in isolation and in small groups of different sizes, and their growth, food intake and feeding activity were measured for several eeks.

3. Initially, chicks of both strains grew faster when they were grouped than when they were in isolation, as a result of a more efficient conversion of food rather than as a result of increased consumption.

4. Later, chicks in the largest groups converted their food less efficiently, possibly because of increased disturbance.

5. From 6 to 12 weeks, when the chicks were in larger cages, growth rate was not affected by group size, but food intake and food conversion were affected differently in the two strains.

6. In general, the isolated chicks ate about the same amount as the grouped ones, and it is doubtful whether social facilitation of feeding occurred at all in these experiments.     

Effects of dietary supplements on the nutritive value of jack beans (canavalia ensiformis) for the young chick

1. Two experiments were conducted with young chicks to examine the efficacy of dietary supplements of amino acids, creatine and potassium acetate in the alleviation of adverse effects of auto‐claved jack beans (AJB).

2. Creatine supplementation of AJB diets markedly enhanced the efficiencies of food and nitrogen utilisation of chicks, restoring these indices to control values. The improvement in nitrogen utilisation was enhanced further on providing creatine with a mixture of 2‐aminoiso‐butyric acid, arginine and lysine.

3. Potassium acetate induced striking improvements in the nitrogen retention efficiencies of chicks fed on AJB diets.

4. Liver weights, as a proportion of body weight, generally increased on feeding AJB diets, the effects being marked with the AJB diet supplemented with arginine and lysine.

5. Hepatic urea concentrations were elevated in all groups receiving AJB. Canavanine, a toxic amino acid component of AJB, could not be detected in acid hydrolysates of livers from chicks fed this legume.

6. Temperature and the volumes of water employed in the preparation of AJB are important determinants of its nutritional value.     

Effect of autoclaving,hot‐water treating,parboiling and addition of ethoxy‐quin on the value of rice bran as a dietary ingredient for chickens

1. Three experiments of 3 or 4 weeks’ duration were conducted with broilers fed on diets containing 60% of rice bran treated in various ways.

2. Autoclaving rice bran for 3 to 20 min significantly improved its feeding value as measured by growth rate of chicks; bran from parboiled rice was equivalent to the autoclaved rice bran and was not further improved by autoclaving.

3. The growth inhibition of rice bran is not due to its trypsin inhibitor activity.

4. Lipase activity in rice bran was destroyed by autoclaving or parboiling and may be a useful index to predict the adequacy of treatment to improve growth.

5. The metabolisable energy of the rice bran samples was about 12.55 kJ/g and was not influenced by treatment.

6. Ethoxyquin did not improve growth of chicks fed on diets containing rice bran and was less effective than autoclaving or parboiling in preventing the development of rancidity.     

Effects of high inclusion rates of salseed meal in the diet of chicks

1. Starter diets containing either maize or salseed meal to replace the maize were fed to chicks over a period of 2 weeks.

2. Growth rate, food intake, food utilisation and proportion of dietary nitrogen retained were much poorer in chicks receiving salseed meal.

3. The chicks receiving salseed meal developed pathological lesions in liver and kidney.

4. The red blood cell count, white blood cell count, haemoglobin concentration and packed cell volume of the chicks receiving salseed meal were lower than those of chicks receiving maize.

5. The apparent metabolisable energy value of salseed meal was determined as 6.83 MJ/kg.     

Time budget and colour preferences (with specific reference to feeding) of ostrich (struthio camelus) chicks in captivity

1. Time budget analysis of the typical behaviours of young ostrich chicks showed that chicks spent over 50% of their time foraging and walking.

2. Food presented in bowls was largely ignored whereas food scattered on the floor was readily taken.

3. A colour preference test showed that green was the preferred colour.

3 Reprint requests to Dr Deeming at Hangland Farm Ostriches Ltd, Upper Wardington, Banbury, Oxon OX 17 1SU, England     

Recycled dried poultry manure in chick starter diets

1. Dried poultry manure (DPM) collected from 1‐d to 3‐week‐old chicks, reared in electrical battery brooders, incorporated at a level of 0, 5, 10, 15 and 20% in a chick starter diet, was recycled four times.

2. There was a linear decrease in body weight and efficiency of food utilisation with each percentage increase in DPM.

3. The amount of dried droppings recovered as a percentage of food consumed was proportional to the amount of DPM included in the diet and remained fairly constant during the recycling.

4. Body weights and efficiency of food utilisation were substantially the same during the first three recycling periods but declined significantly during the fourth period.

5. Mortality was negligible and all chicks appeared healthy and vigorous.

6. Chicks fed on 10% DPM in an isocaloric and isonitrogenous (protein‐N) diet grew and utilised food as well as those fed on the basal diet; chicks fed on 20% DPM did not consume enough to meet their requirements.     

Feeding and pecking behaviour in ostrich (Struthio camelus) chicks in captivity

1. Three sets of experiments were performed on two batches of ostrich chicks to investigate the factors affecting the pecking and feeding behaviour of grouped individuals.

2. Chicks showed no significant alteration of their feeding behaviour in response to raising pen walls in the rearing facility from 30 to 60 cm.

3. Further analysis on a different set of birds revealed consistent short term individual differences in the frequency of feeding and non‐feeding pecks.

4. There were significant pen effects on behaviour suggesting the possible development of a pen ‘culture’ of pecking behaviour.

5. Pecking behaviours in 26 to 33 d‐old chicks, with the exception of drinking, were generally negatively correlated, so any non‐food pecking by a chick was generally associated with fewer pecks targeted at food.

6. By the age of two months chicks were pecking at food on the floor to a far greater extent than at any food presented in food trays.     

Effect of egg composition on hatchability and on growth and slaughter characteristics of meat-type chicks

1.?Using the so-called TOBEC (Total Body Electrical Conductivity) method, which allows the determination of egg composition in vivo, correlations between egg composition, hatchability and hatched chicks’ development were studied.

2.?A total of 1500 hen eggs (Ross-308) were measured by TOBEC, and eggs with extremely high (10%, n = 150), extremely low (10%, n = 150) and average (10%, n = 150) electrical conductivity values were chosen for further investigation.

3.?During the incubation period, it was observed that eggs with high electrical conductivity had a significantly higher mortality than eggs with low electrical conductivity.

4.?It was observed that both the increase in electrical conductivity at the same egg weight, and the increase in egg weight at the same electrical conductivity resulted in an increase in the hatching weight.

5.?It was found that the dry matter, protein and fat content of the chicks hatched from eggs with low electrical conductivity was higher at hatching than that of the chicks hatched from eggs with high electrical conductivity.

6.?At 42 d of age the liveweight of cocks and pullets hatched from eggs with low electrical conductivity was 3·2 and 8·2% higher than the liveweight of cocks and pullets hatched from eggs with high electrical conductivity.

7.?Because of the higher liveweight at slaughter, there was a significant superiority of the chicks hatched from eggs with low electrical conductivity in the case of the examined carcase traits at slaughter.

8.?Similar tendencies were found also in the ratios of carcase variables to liveweight, but the between group differences were not statistically significant in this case.

9.?Based on the results it was concluded that TOBEC seems to be a useful method for separating eggs with different composition.

10.?This could be a good starting point for further in vivo investigations in order to clarify the effect of egg composition on hatchability and further development.     

Short‐term stressor effects of propranolol

1. The effects of propranolol (10 mg/kg) on plasma cholesterol, glucose, corticosterone and free fatty acids, on adrenal mass and cholesterol content and on body temperature were determined over a 24‐h period in 3‐week‐old Light Sussex chicks.

2. Changes in plasma cholesterol were equivocal, though there was perhaps a trend towards hypercholesteraemia.

3. Birds became hypoglycaemic within an hour but were hyper‐glycaemic between 2 and 4 h. At 24 h they were normoglycaemic.

4. Plasma corticosterone was increased markedly at 1 h but was decreased compared with the control at 2 h (P<0.01). Thereafter the concentration was in the normal range.

5. There was an enhanced hyperlipacidaemia in the treated birds after 1 h.

6. Adrenal cholesterol stores were decreased by 10% at 4 h but were unaffected at all other times.

7. Colonic temperature decreased by 1–6 °C after 2 h but was normal by4h.

8. It is concluded that propranolol has mild stressor activity which is lost within 24 h.     

Immunoresponsiveness of fast‐growing chickens as influenced by feeding regimen

1. Immunoresponsiveness and disease resistance were measured in broiler males maintained on ad libitum feeding throughout or on alternate‐day feeding. Alternate‐day restrictions were started 1 and 2 d after hatch so that on any one day there were chicks fed and fasted.

2. Severity of response to E. coli challenge as measured by lesion scores, and mortality was greater for chicks fed ad libitum than those fed on alternate days. For chicks fed on alternate days, lesion scores were lower for those without access to feed for the 24‐h period immediately after challenge.

3. Spleen weights, the indicator of response to marble spleen disease virus challenge, were higher for chicks fed ad libitum than those fed on alternate days.

4. Antibody response to sheep red blood cell antigen was not affected by feeding regimen.

5. Ratios of heterophils to lymphocytes were higher for chicks given access to feed for the previous 24‐h period than for those fasted during the previous 24‐h or those that had been fed ad libitum.

6. Results of this experiment suggest that for alternate‐day feeding programs, vaccination be administered on the day that chicks are not fed.     

The relationship between hatching egg weight and subsequent performance of broiler chickens

Small eggs constitute a high proportion of the eggs laid by pullets. The literature shows that chick hatching weight is strongly correlated with egg weight, but evidence on the influence of egg weight on hatchability and subsequent performance of chicks is less certain.

The aim of this experiment was to determine the profit returned at 12 weeks by broiler chickens hatched from eggs ranging in weight from 44 g. to 58 g. at one gram intervals and to determine how competitive and separate rearing might modify the relationship.

A total of 6000 eggs were collected during 10 days from a 28‐week‐old, broiler breeding flock and graded into the above mentioned egg weight classes. From these, a total of 3480 day‐old broilers were housed. Each egg weight class was equally represented and balanced for sex.

Hatchability and fertility showed no consistent trend with egg weight for eggs above 46 g., but below the 47 g. level there was a trend of declining fertility and hatchability.

A strong positive relationship was found between the weight of the chick at 1 day of age and egg weight for both males and females with no significant difference overall in body weight between the two sexes.

Body weight to 12 weeks was found to be strongly related to egg weight, in a linear fashion, though this influence declined with age.

There was a greater influence of egg weight on body weight at all ages in the separate rearing treatment compared with competitive rearing but this was not significant after 10 weeks.

Egg weight had an important bearing on body weight and profit at 12 weeks, but no effect on food conversion or mortality.

The increased profit over food costs per 100 day‐old chicks was found to be 52.75 cents for the separately reared birds respectively for each 3 g. increase in egg weight.     

Scanning electron microscopy of the respiratory epithelium of chicks fumigated with formaldehyde vapour

1. Hatching chicks were exposed to 10.9 ppm of formaldehyde vapour during the last 3 d of incubation in a commercial situation.

2. Samples from pre‐selected regions of the entire respiratory tract, taken at 0, 6, 30 and 54 h post‐vaporisation of formaldehyde, were examined by scanning electron microscopy for surface morphological features and associated pathological changes.

3. Clumping of cilia, blebs on the cilial wall, deciliation and exfoliation of the epithelium were all observed under the scanning electron microscope.

4. Lesions were more severe in chicks exposed for 54 h as compared to those exposed for 6 and 30 h. There were no regional differences in the lesions throughout the respiratory tract of all the chicks.

5. Limited observations suggest that the passage of formaldehyde vapour across the egg shell wall may influence the morphology of the respiratory lining of the developing embryo.     

Urea and aspartic acid supplementation of low‐protein broiler diets1

1. L‐Aspartic acid does not seem useful as a protein surrogate in conventionally formulated low‐protein diets for broiler chicks.

2. Urea as a protein substitute does not enhance the value of conventional broiler diets.

3. Urea does not improve broiler diets that have been supplemented with fish meal or crystalline amino acids to satisfy requirements for all indispensable amino acids.

4. Urea is absorbed into the bloodstream, but is not assimilated into body proteins.     

Traits influencing the hatching performance of Japanese quail eggs

1. Japanese quail eggs from moderately heavier sires showed superior fertility; while fertile eggs from moderately heavier dams hatched slightly better than the eggs from lighter dams.

2. Higher rates of fertility and hatchability of Japanese quail eggs were observed from parents of 10 to 19 weeks of age, with peak fertility and hatchability at 14 and 12 weeks of age, respectively.

3. Sex ratios of 1:2 to 1:5 gave comparable fertility and hatchability results.

4. The hatching performance of quail eggs from cage and deep litter reared breeders was comparable.

5. Fertility and hatchability were directly proportional to the egg weight.

6. Quail egg shell colour, tints and blotches were found to influence hatching performance.

7. Storing quail eggs at 16 ± 2°C and 75 ± 5% relative humidity for more than 4 d reduced hatchability.

8. Hatchability of eggs stored at room temperature was improved if they were sealed in polyethylene bags.

9. Provision of light during the first 14 d of incubation resulted in a photo‐acceleration of about 3.2 h.     

Corticosterone and fat deposition in broiler chicks: Effect of injection time,breed, sex and age

1. Corticosterone (680 μg/kg body weight per day) given as six daily injections to 3‐ or 7‐week‐old chicks decreased weight gain, but increased food consumption, abdominal fat pad weight, skin dry matter, relative liver size and liver fat concentration.

2. Time of day of injection did not modify the response to corticosterone of 3‐week‐old chicks kept under natural daylight nor of 7‐week‐old broilers receiving additional illumination.

3. Pure White Rock chicks and Cornish x White Rock crossbred chicks responded similarly to corticosterone injections at 3 weeks of age.

4. Seven‐week‐old female birds treated with corticosterone had significantly larger abdominal fat pads than similarly treated males.

5. Corticosterone injection was more effective in increasing the proportion of liver fat in 7‐week‐old birds than in 3‐week‐old ?hicks.

6. The increased amount of abdominal and liver fat due to corticosterone injections administered at 3 weeks of age disappeared after 3 weeks, but growth depression was still evident.     

Dexamethasone‐induced alterations in glucose tolerance and,insulin, glucagon and adrenaline responses during the first month in white leghorn chicks

1. Alterations in glucose tolerance and, insulin, glucagon and adrenaline responses in dexamethasone (DXM)‐treated (induced hypocorticalism) chicks have been evaluated chronologically during the first month of development of White Leghorn chicks.

2. Alterations in glucose tolerance and, insulin resistance and glucagon and adrenalin responses in dexamethasonised chicks were recorded. Control chicks too displayed differential glucose tolerance and, insulin, glucagon and adrenaline responses on a chronological basis.

3. The observations suggest increased insulin and adrenaline sensitivity in the first fortnight and gradually increasing glucagon response in the second fortnight in neonatal chicks.

4. Furthermore, increased insulin sensitivity and attenuated glucagon responsiveness was also associated with DXM‐induced hypocorticalism.     

Effects of adding yeast cell walls and Yucca schidigera extract to diets of layer chicks

1.?This research was conducted to determine the impact of diet supplementation with yeast cell walls and Yucca schidigera extract on the growth performance, antibody titres, and intestinal tissue histology of layer chicks.

2.?White, 1-d-old, Hy-Line hybrid chicks (n?=?840) were divided into 4 main groups, each comprising 7 replicates of 30 chicks (n?=?210): (1) control; (2) 1000?mg/kg yeast cell walls (YCW) added; (3) 1000?mg/kg Yucca schidigera extract (YE) added; and (4) 500?mg/kg YE?+?500?mg/kg YCW added. The trial lasted 60?d.

3.?Daily weight gain of the chicks was positively affected between d 45-60 in the YE and YCW?+?YE groups compared with the control group.

4.?Overall, feed consumption did not differ between the control and YCW, YE, YCW?+?YE groups during the 60?d study period. Feed efficiency was better in the YE and YCW?+?YE groups than in the control group between d 1-60.

5.?During the 60?d evaluation period, live weight gain, and final live weight were higher in YE and YCW?+?YE groups than in the control group.

6.?Antibody titres against infectious bronchitis and infectious bursal disease did not differ among the 4 treatments, but those for Newcastle disease were higher in the YE?+?YCW groups than in the control, YCW and YE groups on d 45.

7.?There were differences in intestinal histomorphometry between the 4 treatments. The height of the jejunal and ileal villi was greater in the YE and YCW?+?YE groups than in the control and YCW groups

8.?It can be concluded that YCW and YE supplementation for layer chicks is beneficial for growth performance and intestinal histology during the 1-60?d growing period.     

Antimicrobial substances and chick growth promotion: The growth‐promoting activities of antimicrobial substances,including fifty‐two used either in therapy or as dietary additives

1. Fifty‐five antimicrobial substances were tested for their ability to promote growth when added to the diet of chicks.

2. Both cephalosporins and all the nine penicillins tested were active.

3. Of six aminoglycosides, streptomycin and gentamicin had the greatest activity and neomycin had none.

4. Growth rate was significantly improved by clindamycin, lincomycin, vancomycin, spectinomycin, rifampicin, oxytetracycline, chlortetracycline, erythromycin, tylosin, flavomycin, virginiamycin and zinc bacitracin. Chloramphenicol and nalidixic acid were inactive. Polymixin B, novo‐biocin, cycloserine, phosphonomycin, and sodium fusidate had little activity. Fusidic acid promoted growth at 250 mg/kg diet.

5. Trimethoprim was inactive alone and in combination with sulpha‐diazine. Of seven 5‐nitroimidazoles, only dimetridazole and metronidazole showed slight activity. Of the six 5‐nitrofurans, only nitrovin, the standard reference substance used, promoted growth.

6. Caprylohydroxamic acid, a urease inhibitor, had no beneficial effect on growth rate or on the efficiency of food conversion.

7. The growth‐promoting properties of the various substances could not be related with their known antimicrobial and absorption characteristics in mammals.     

Effect of feeding regimen and lighting pattern on the performance of broiler chickens in the hot,humid tropics

1. A food restriction study in conjunction with light control was conducted with commercial broiler chicks in a tropical environment.

2. Chicks on treatments 1 and 2 were fed continuously while those on treatments 3 and 4 were fed during the day (from 06.00 h to 18.00 h) and night (from 18.00 h to 06.00 h) respectively. Chicks on treatment 1 received only natural light during the day, while those on treatments 2, 3 and 4 received supplementary lighting during the night in addition to natural light during the day.

3. Food consumption by birds on treatment 2 was significantly higher at 56 days of age, followed by birds on treatments 1, 4 and 3.

4. The pattern of body weight gains was similar to the order of food consumption.

5. Efficiency of food utilisation was poorest for birds on treatment 2.

6. Mortality rates were not influenced significantly by the feeding regimen and lighting pattern.

7. Dressing percentage and proportion of abdominal fat were greatest for birds on treatment 2.     

Heating effect of microwave radiation in broilers

1. Two experiments are reported in which a total of 1020 broiler chicks was used to examine the heating effect of microwave radiation.

2. In experiment 1, the effects of exposure time and age of birds were studied. In experiment 2, the influence of body mass and the effect of multiple exposures were explored.

3. In the first experiment, microwave treatment caused the birds’ body temperature to rise significantly only at 0, 1 and 2 weeks of age. Body temperature increased linearly with exposure time.

4. Signs of thermal stress were evident during exposure for 80 or 100s up to the age of two weeks.

5. The heating effect of microwaves in the second experiment decreased as the total irradiated body mass increased. For the same body mass, however, the heating effect was greater at the younger age.

6. The effect of using multiple exposures in experiment 2 was additive and varied with the age and body mass of the birds.

7. A model for the heating effect of microwave radiation is discussed which takes into account all the factors studied.