I went to the barn tonight to find 1 of my 3 roosters (a rhode island red) laying on the ground. This was odd to me because they never lay inside the chicken coop on the ground. I went over to him and nudged him to make sure he was ok, and he just stood up. However, he would not move until I pushed him. Even then, he still would only go as far as I would nudge him to go. Finally it was like he snapped out of a transe and walked away, finally flying up to roost with the others. A short time later I looked back and my Lakenvelder rooster was laying under the roost. I went over to him, and nudged him, but he nearly fell over. I picked him up, and he wouldnt use his strength, and balance to stay upright. I almost dropped him, but layed him back down. As soon as I layed him down he rolled over, let out a muffled squawk, and died. My flock has been very healthy, and are all about a year old. I have no poison that they could access. What could cause this? Should I be worried that the rest of my flock may be in jeopardy?