I have a 4 day old RIR chick that raises it's head and gapes it's mouth open. It's been with it's sibling in the brooder, and it has been eating and drinking just fine. All the others are doing great. I first noticed it when it would get under the heat plate and it wouldn't lay down... then it's head would slowly drop until it's beak was resting on the floor. Soon after, it started gaping. I don't see anything lodged in it's mouth or throat, but after examining it this morning, I found a hard knot on the left side of it's stomach between the keel bone and thigh. It feels to be close to 1/2" long (running parallel with the keel). I first noticed it by the (approximately) 1/4" lump in the skin on the end (rear). I wondered if it might be an impacted bowel, but it has pooped, and it looks normal. Here's a video of how the chick is behaving:
