I have a 19 week old rooster who will not extend his neck. I thought it was sour crop creating the lump in his neck but now I realize he won't extend it and the lump is just the bend in his neck. He's also sleeping air more than the others and he is not eating nearly as much. Please help. I need to know if I need to cull him sooner rather than have him infect the whole flock with something.