Thank you for all the replies and compliments. Her name is Natasha. Some of you suggested feeling her breastbone. What are we looking for in the breastbone? Also, I don't know if it's important, but she doesn't sound like a chicken - she still makes peeps, while her broodmate sounds like a...
To further explain things, she is about 2 pounds or less and only about six inches high. Attached is a picture with her brood mate (a Light Brahma), who is actually two days younger than her! We are very worried about her.
We have a three-month old Barred Rock pullet that has refused to grow much at all. She doesn't eat much, and as a result is not much bigger than a chick. We are wondering if there is a problem, and what we can do about it. We are worried that she will be too small by the time she gets to egg...