Sick chicken, drooling?

Interesting ideas, He has some wing feathers out of place I mean a good sized gap, which is how I noticed him acting weird to begin with. I'm wondering if he may have gotten kicked by one of the horses. Those chickens love to lay in in the stalls after they eat all the good stuff out of the poop.
Apollo has eaten great today, he looks as good as new maybe just alttle tired- isn't that weird? We thought he was gong to die for sure. We will put him in the coop tonight.
He has pooped today and no drooling. When they are in alot of pain could they act like that? Labored breathing, drooling, unable to walk?
My neighbor had mentioned the mushrooms, we really don't have any. We don't use any poisons since we've gone chicken. They seem to take care of most bugs but I did find mosquito larvae in the rain gutters this weekend and I used some DE- but this DE was all natural - kind you can put on cats and dogs but the warning label did say it was not to used near body's of water it could harm fish.

Thank you for your concerns- Hope that one day I can help someone like you all do!

I have two that I just added to my flock and for some reason no one seems to want to challenge the pecking order so my two new sexlink have stayed up in the enclosed portion of my coop where I think it would be warmer and they are drooling I have plenty of water and food but does this mean they are sick?