Kansas is the only state that I've seen that makes that illegal. Probably others do but I've not seen it. I once hunted pheasants in Nebraska on a paid hunt. The host said he averaged about 90 roosters per year. I was impressed until later he also said he had never hit a pheasant in the air and his wife was the best at spotting pheasant heads stcking out of the weeds at 35 mph that he had seen. I think it has been very common practice by locals in much of the west and midwest. It will probably become less common as bird hunting continues to have more economic value. It will probably become more like Europe where doing something like that would be the same as stealing from the landowner and not tolerated. You won't find many bird hunters with dogs that will tolerate hunters shooting birds on the ground either because of the danger to dogs. One of my patients had a bird dog killed a couple of years ago by a friend shooting at a crippled, running rooster.