Yep, you are correct.The fact that it happens in nature all the time is the reason I stopped thinking it was a terrible thing and likely going to cause birth defects. I have a friend who has a flock of about 30 Peas they have had these birds on the family farm for like 25 years now, they do not control breeding at all, but have on occasion brought in a new hen. Usually they collect eggs to control population, but when they do allow them to hatch they don't have anymore chicks with issues than I do and that's seldom. We figure there are quite a few generations of inbreeding going on there.
