I have a hen and rooster that have been in a pen with each other eating grower pellet, they are about 6 months old. Yesterday I saw the rooster was kind of drawn up. Like he was extending his neck out and he was kind of hunched over and his wings were almost dragging the ground. Brought him in gave him a shot of tylan and put teramicyn in his water and tried to feed him. He died last night and now I went out there to check on the hen and she is doing the same thing. Any clue?