Plenty of chickens and roosters living in the wild on Hawaii. Perhaps because there are no snakes to eat their eggs helps. The island of Kauai has wild chickens as well. When I inquired about it, I was told that a hurricane accidentally set a whole farm of them loose. That happened 8 years prior.

This wouldn't get rid of every farm or family raising chickens. It would be just another option on the free market. Regular chicken would continue to be raised and eaten. As evidenced of people on this board, there's going to be a sizable portion of the population who would continue eating farm raised chicken. The market would continue to supply that chicken. As this article says, the lab grown chicken is still fairly expensive. Some people will pay that premium to eat meat that wasn't slaughtered, but the cheaper, farm raised chickens would stick around. Or people raise their own chickens. So chickens will continue to exist.