Olfactory experience of chicken embryos influences food preferences after hatching

Abstract : In ovo or in utero chemosensory learning has been described in a wide range of vertebrate and invertebrate species. However, in birds very little is known about the consequences of early exposure to chemical stimuli on the development of behaviors. Using domestic chicks (Gallus gallus domesticus), the main model of avian development, we have shown that exposing eggs to chemosensory compounds via the air consistently alters chick feeding activity. Firstly, we will present work showing that the concentration of a chemosensory stimulus in the environment surrounding the embryo affects whether hatchlings will approach or avoid food with or without that same olfactory stimulus. Secondly, we will provide evidence that chicken embryos are able to detect and form a chemosensory memory before breathing in the egg and while still surrounded by amniotic fluid. Finally, we will present work demonstrating that chicks exposed in ovo to menhaden oil via the maternal diet preferentially oriented their feeding behavior towards food containing menhaden oil when confronted with an unfamiliar food. In ovo, chemosensory learning may have evolved to prepare offspring for their environment. This suggests a common principle of embryonic chemosensory learning across vertebrate taxa.