I'm not sure if you're talking about something else when you're talking about freakish die-offs, but if they're dying after the coon was there, it might be from stress. We had the same problem last spring. We did NOT want to kill the coons, which we trapped; a mom and her baby. So, in the middle of the night 3:00AM, to be exact, we carted them off to the middle of nowhere. WE had hired a trapper and used his live trap, as well as one of ours. Well, when we got to where we were going to let them go, we could not open the trapper's trap. We could not figure it out. We let baby out, and he/she stayed right there, waiting for mom. WE finally had to give up on the trapper's trap, and decided to call him in the morning, stop him from coming over, and figure out a way to ask him how to open the trap, without letting him know we caught anything. Baby in the meantime went back in the cage, and we carted them home again. Next day we overslept. Next morning, there was the trapper bright and early, and when my son went out to talk to him, the trapper pulled out a gun and shot both coons right in front of him. It was heart breaking and I thought incredibly insensitive on the part of the trapper, even though we know the law states they have to kill them, he could've taken them away to do it. Anyway, point is, you really do have to get rid of the coons, one way or another, cause they'll just keep coming back and they are devastating; they killed at least 15 of ours. So I guess it was a blessing in disguise in our case. Next thing you have to do is make your chicken enclosure as predator-proof as possible; not as impossible as it might seem. Elevating the coop is one answer; or burying a fence three feet into the ground all the way around; you can also use electric fence, or dig a trench around the perimeter, and fill with cement. Good luck, and hope you get some more chickens once you fix up your coop. If you live trap anything, the trapper suggested tuna fish or catfood; both work well.