Gasoline motor machinery parked in the yard where chickens free range can kill a baby chick. Not so much the machinery itself, but they all leak motor oil or transmission fluid or some sort of toxic pollutant onto the soil that is toxic if ingested by a small chick. Yesterday, one of the two chicks hatched out of twelve eggs a month ago died. I had first noticed it was unable to use one leg as I started handing out meal worms to the two chicks and the broody. They had been out free ranging a couple hours previously, and I had seen the trio over on the side of the yard where I keep the log splitter, but I've never looked at it as a hazard. The chick showed all the symptoms of neurotoxin poisoning. First it could not stand, then it lost other motor abilities such as holding its head up, and it kept falling asleep. After another hour, it was all but dead, but having convulsions occasionally. I finally euthanized it. It broke my heart, and I was frantic to find what had made it so sick, fearing I could lose the other chick or even adult chickens. I spent over an hour going around looking for toxic weeds. There was little chance of finding any because weeds haven't got much of a chance around me since I yank any I see as I walk by. I considered the possibility that one of the adult chickens had given the chick a punishing peck on the head causing brain damage, but after very close examination, I couldn't find any mark on its head or body. Toxic insects? It's been too cold, nothing but an occasional fly. This morning, I combed the area with an eye for anything that could produce a neurotoxin that was in the area where the chick had been wandering. That's when I spotted the log splitter. They all leak. This one leaks transmission fluid, not much but enough to contaminate the soil under it. Chicks sample everything like little vacuum cleaners, so it's conceivable it had gobbled up a few bits of grit that were coated with the toxic substance. I now have fencing surrounding the offensive machine. Maybe you might want to give your yard a thorough tour for such potential chick killers.