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Pecking and prehension of feed particles in domestic fowls

INRA Prod. Anim., 10(5), 403-414.


1 INRA Station de Recherches Avicoles 37380 Nouzilly

2 INRA Laboratoire de Technologie Appliquée à la Nutrition BP 71627, 44316 Nantes cedex 3


Poultry feeding is at the same time a simple (one single feed) and sophisticated (precisely controlled) model. Feed pecking, a bird specific activity, is complex and requires a detailed analysis to define methods of evaluation of feed prehension. Chicks hatch thanks to their beak. Their first activity after hatch is to peck. Sensorial and metabolic reinforcements are more or less rapidly acting on feed selection depending on the growth potential of the chick.

Feed pecking is a discontinuous, anticipated, heterogeneous and selective activity. Rhythms of access to the feeder rather depends on adaptation of the animal to its environment than on an internal regulation of appetite. Slow motion video observation of feed pecking confirms that during the two third of the pecking time, the head of the chicken remains in a steady position which permits observation of the particles. The particle to be taken or touched is chosen prior to the peck which is performed with closed eyelid. Most of the pecks do not seize a particle but can be characterised as "exploratory" pecks and correspond to a global requirement for "beak related activities". Strength of a peck can be measured by a fast balance. Strength and rhythm of feed pecks vary according to the type of feed particles eaten.

Three measurements can be done to quickly characterise feed prehension :
Feeding rate = Amount of feed eaten / Time eating,
Pecking rate = Number of pecks at feed / Time eating,
Pecking efficiency = Amount of feed eaten / Number of pecks at feed.
These measurements will be further improved taking into account ratios between exploratory and intake pecks and pecking strengths.

Under practical rearing conditions, scanning of the number of chicken at feeders in several sites of the shed give an estimation of the time spent eating. Increased number of social interactions at the feeder and floor pecking just after eating are indicators of a problem of adaptation to the diet.

Control of feed prehension in fowls will contribute to a better assessment of physical structure of feed particles which will complement the already available extended knowledge of biochemical nutrition.

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