I don't know when exactly a TOM gets too old...LOL. Our oldest boy is Clyde. He is a 5 year old Rio Grande and still does his duty. I have heard that some breeders will only use a Tom for 1 or 2 seasons, then retire him (u can decide how to define "retirement") and start the 3rd season with new boy. The reason is that the Toms get big and pretty heavy by the end of year 2 and they don't want their hens damaged. This is our Heritage Bronze boy's 2nd Spring and he is getting to the 30 lb mark, so we will have to decide if we will "retire" him or not. As for replacements,,one of his sons. But if we didn't have extra males here..we'd look for a breeder and buy one that way.
At what point does genetic diversity become a consideration? Would simply replacing a tom with one of his sons bring issues with inbreeding?