Visual pecking preferences in domestic chicks. Part II. The role of experience in their maintenance or not.

The role of swallowing experience on the maintenance or switching of the basic visual preferences in the pecking of young chicks has been investigated using both visually attractive and less attractive seeds. It has been shown previously that chicks switch their preferences 24 hrs. later if they cannot swallow what they visually prefer whereas debeaked birds which are able to swallow large attractive seeds maintain their preferences. However, the same experiment made with glued seeds shows that the ability to swallow was responsible for the maintenance of preferences in debeaked birds. Swallowing appears to have a rewarding effect. The possibility of swallowing the visually preferred item seems to be the proximate factor which will determine whether experience reinforces basic visual preferences or, on the contrary, modify them.