Many breeders, at least in my circle, want to promote their breeds and help others.Why would you donate good breeder birds??
In Jersey Giants, the only breed I have personal experience with, I've seen breeders sell chicks for anywhere from $10-$30 each. Juvenile pairs are typically $50-$100. A mature pair would likely be $200+. The upper end of those prices is usually from breeders who have quality stock and have proven multiple birds in multiple shows. Winning one show with one bird does not make a good breeding program.