Influence of socially involved hand-raising on life history and stress responses in greylag geese
Animals are hand-raised in a variety of contexts, including experimental research. This has been criticized frequently as producing animals with species-untypical behaviour. Here we compare life histories of 330 hand-raised and 631 goose-raised Greylag geese from a free-flying flock
to determine whether hand-raising affected life history, reproductive variables and behaviour. We found little differences in life histories (e.g. male age, age at pair bond) or reproductive variables (e.g. number of eggs, egg weight, number of young hatched and fledged) of hand-raised and
goose-raised geese. However, hand-raised females had lower life expectancies than goose-raised ones, mainly due to predation during breeding. Hand-raised geese were stressed significantly less during social, handling and predator stress, were attacked less by conspecifics and were less vigilant
than goose-raised geese. We conclude that hand-raising resulted in geese with species-typical life histories but reduced stress responses. This makes hand-raised geese cooperative partners for research, but also more vulnerable when exposed to predators.