I have hen over a year old that started laying in January. We’ve had no problems until last week she was egg bound, fluffed up, appeared to be in labor trying to push the egg out, standing to herself and not being active. She did lay it right before dark after I put her in a warm water bath. The egg appeared normal. She has done this 3 more times over the past week. I have not given her any more baths. I have put oyster shells in the run for her. I had not changed her diet. What would cause this? How to you prevent it from happening?