I have this sweet RIR I have had since she was 1 day old. There were a couple of issues right away, she had trouble standing up and kept falling on her back. The other chicks would peck at her and we had to protect her for a day or so until she started walking around. Her name is Turtle, for this reason.
She has always had slight balance issues and has grown much more slowly than the other chicks. She wasn't much smaller than them at first, but within a week it was obvious she was going to be little. What I'm wondering is if she's a bantam or just stunted in her growth?
Here are a few picks comparing her to other chicks that hatched the same day. She's 11 weeks as of today. At 9.5 weeks old, she weighed 1.4 lbs.
She's the one in the back, so the perspective is a little off, but she was quite a bit smaller than the others I had.
This is my Cornish Cross, Barred Rock and Turtle.
She's the brown one snuggled in on the right. All five of these hatched on the same day.