I just looked up duramycin 10 and learned that it is for respiratory illness. Do any of your hens have any signs of respiratory illness such as gasping, runny nose or eyes, rattling or wheezing when breathing, etc? Otherwise, I don't think it will help her if she has something egg or crop related. I could be wrong though. I'm no expert. I do know if she broke an egg inside her she would need a very strong antibiotic like baytril and, even then, she may still die. How is she acting today. If she has perotinitis, she would probably be acting really really sick unless it just started. Let's just hope it's something simple and she'll get over it! I wish to heck somebody else would chime in here!!!!!