My 11-month rooster can't keep his head up. He either stands with his head down on the ground between his legs, so that the head is upside down, or he sits and puts the head on the ground. He also has diarrhoea. When I pick him up he raises his head and looks all bright and alert for a minute and then his head droops again. He will drink water if a bowl is brought to his beaks, but is off other food. I've isolated him and and am providing extra heat, but he is still pretty listless. The other two roosters seem to be doing okay. We've had a cold/windy spell and part of the rooster house was being repaired so I am desperately hoping that he just caught a cold.