Studies on the feeding behaviour of the domestic fowl
Abstract
This study was preparatory work for a much longer period of research, the aim of which is to make a detailed study of the feeding behaviour of motivationally abnormal chickens. The conditions of aphagia and hyperphagia are well known in mammals, yet, to date, no detailed study of the feeding behaviour of such animals has been undertaken. Such a study is proposed for the chicken, and to this end, in order to facilitate the study of abnormal feeding behaviour, studies on the normal feeding behaviour have been undertaken.
Two studies on the normal feeding behaviour were carried out on Brown Leghorn cockerels. An apparatus for measuring pecking strength and rate of food consumption was constructed and employed in both experiments. It was found that reliable differences between 23 24 and 48 hours deprivation did not arise with any single measure of behaviour when the cockerels were fed mash, although amount of food consumed and overall pecking rate did differ reliably between the 2 hour and the two longer deprivations. However, when the cockerels were fed pelleted food, significant differences did arise in food consumption and pecking rate between 24 and 48 hour deprivations. It was suggested that since pelleted food was consumed far more rapidly than mash, the different results between pellets and mash might be attributed to a crop distention factor which did not come into play when the cockerels were fed mash until other, less sensitive feed-back mechanisms were already operating. No consistent differences in pecking force or in other measures of feeding behaviour used were found between 24 and 48 hours deprivation. It was concluded that pecking rate and amount of food consumed were reliable parameters of feeding tendency up to at least 24 hours deprivation when the food was in pellet form.
Another possible parameter of feeding tendency was obtained from a third experiment when cockerels were fed quinine—adulterated food. However, significant differences between all 3 deprivations (2, 24 and 48 hours) arose only in the second part of the experiment. It was concluded that the reliability of the method must remain in doubt.
In an attempt to obtain hyperphagia, Brown Leghorn cockerels were injected with gold-thioglucose solution. Both intravenous and intraperitoneal injections were given but feeding behaviour remained normal. Furthermore, when the brains were examined, no evidence of gold-thioglucose lesioning was found. It was concluded that the mouse and the chicken have different reactions to gold- thioglucose.
In preparation for lesioning the chicken hypothalamus by standard electrolytic techniques, a stereotaxic atlas of the Brown Leghorn cockerel hypothalamus was constructed. Interpretation of the hypothalamus agreed with classical interpretation and no new proposals regarding hypothalamis cyto-architecture were made.