Summarize this article:

If you are concerned that your chicken is egg bound, there are several signs you can look for. In addition to noticing that she hasn't laid any eggs, there are other symptoms of the condition. For example, you can pay close attention to her appetite.  If your hen has not eaten any food or shown any interest in her feed for a day, she could be egg bound. An egg bound hen will likely not drink any water. When you are observing her eating habits, pay attention to whether or not she defecates. An egg bound hen will sometimes have trouble relieving herself. Egg binding is extremely uncomfortable for chickens. The physical pain can cause her to act differently than normal. If your chicken seems apathetic or depressed, that is a sign that she might be egg bound.   There are other behavioral signs to look for. Take notice if she goes in and out of her nest repeatedly. Remember that hens will sometimes take a break from laying for other reasons, such as an intense heat wave. That is why it is important to look for multiple behavioral and physical symptoms when monitoring your hen. Your chicken might look different than normal if she is egg bound. For example, her face and comb might appear pale. She might also walk differently. Egg bound chickens often waddle, similar to penguins.  Your chicken will appear like she is trying to lay an egg. Abdominal straining is a symptom of being egg bound, along with a hard abdomen. Pay attention to your hen's feces. Egg bound hens will often have watery diarrhea.

Summary:
Monitor her appetite. Observe her behavior. Look for physical signs.