Even the one that had mentioned waiting until 1/4 of the natural lifespan was completed before butcher is ridiculous. They had like 6 years for rabbits, 6 for turkeys, 10 for chickens and 20 for a cow. There were more but I can't remember all of them. Sure, I've eaten rabbits that were over 18 months, but I'm not gonna raise my roosters for almost 3 years before butcher constantly