One of my roosters started getting less and less active.. and resting a lot with his tail down. I could not find anything wrong with him... he was a good weight, eyes bright, no breathing problems, nice red colour to wattles, no mites or live.. he was a white bird so easy to inspect his feathers. He seemed to loose his strength and lost a little weight towards the end. Over a couple of weeks he got less and less active, stopped crowing and one morning he was dead. I did not worry too much as my other 14 chickens were all acting normally. But now I noticed one of the young pullets showing the same behaviour. She is quit, resting lot, not very active and holding her tail down. When I pick her up she seems to have little strength. She also is not a heavy as the other birds her age.. but she is not skinny either. Again there are no other symptoms. I think she will go the same way as the rooster. I inspected the rest of my flock today and they are all plump and healthy. Any ideas what is going wrong here? I have not had anything like this happen before.