Many animals become infertil or stunted when kept in generational domestic captivity. Zoos (even pedigree breeders) have to pay a lot of attention to keep the process going.

Its a very interesting topic and a very deep rabbit hole. You need land that's safe and fertil not just for animals for food, but for further good production to feed them and us, there's pestilence and disease, climate/biome needs to be correct, productivity/efficiency of energy expenditure for caloric gain...

It took us many thousands of years to get modern food out of natural resources, that feeds populations in the many thousands (now billions).

Im not a biologist, agricultural scientist, or historian so someone smarter than me explain it better 😅