I can say that easily; culling a population of free-roaming wild animals because people believe there are too many of them is very different from breeding a pop

I can say that easily; culling a population of free-roaming wild animals because people believe there are too many of them is very different from breeding a population of captive domestic animals with a goal of achieving specific results. As for whether humans are good at breeding when done intentionally, the evidence is a bit equivocal. Mixed breed dogs and cats are usually much less prone to heritable health issues than purebred, but I think that's less true for farm animals where health issues impact profits.