One of my 5 month old male runners is acting off. I arrived home to find him out in the yard by himself. When approached he didn't even open his eyes. I picked him up and he struggled a bit. he is able to stand but is unsteady. Doesn't seem to want to walk. I isolated him from the others(who are all fine). He is now standing, though not in an erect manner as usual and twitching his wings constantly. Any ideas? About 1 week ago one of the other males was a bit unsteady also. It resolved itself within 3-4 hours. I have ducks and chickens and they do interact in the backyard. I did not see any signs of obvious injury. All of the birds eat 18% Nutrena All Flock and have fresh water available at all times. I did not feel anything obstructing his throat.