I have a chick who will be 3 weeks Tuesday. I got her at 1 week. From the beginning she has acted like she was constipated. She does not have pasty butt. When she goes to poop she does so standing up...I have noticed the other chicks all squat down when they poop...and it looks like she is straining...looks effortless for the other chicks. Because she does this standing the poop will often make a mess of her feathers and I clean her up. Other than this she acts normal. She runs and plays with the others, is trying to fly a little, I have seen her eating and drinking. I have also seen her bedded down with the others so I know she can squat when she wants to. She is maturing at the same pace as the others. Any thoughts as to what could be going on with her? I'm at a complete loss.