Baby chick is a good meal for a snake like that. King snake Id probably leave alone. I currently dont have a rodent problem and really only had one when they took up residence in the shed.What??? That really is throwing out the baby with the bath water. Having snakes around is good because they keep the rodent population down. Of course you don't want a rattlesnake, but they are easy to ID, especially for a larger snake: viper head (triangular) and rattles at the tale. But a gopher snake or garter or king snake is good to have around! Inam always happy to see them and guess what? I can't remember which one but one of them keeps rattlers away...
If I didnt have baby chicks on the ground I would probably have left them alone.