Wild food items as everyone has stated parasites. They have been protected and isolated from most harmful bacteria for generations the ability to deal with real world prey items is unlikely.

Most wild snakes have internal parasites and shorter life spans so it is likely the same would happen.

Chicks there has been prey studies done in Africa the northern end of the royal range and in places Royals were found to be feeding on birds mostly sub adults. The study was done by an italian team at the moment their name escapes me. The end result is it is quite likely they will feed on chicks and quite likely do just fine doing so. They are a little low in calcium than rats and mice so if someone was feeding them exclusively a supplement might not be a bad idea. There is a member from south america I think whom is feeding chicks as there are no rodent breeders where he is. Can't recall his name either I think I need to find a coffee...