Went out to replenish the chickens water this morning and found these worms at the bottom of the container. May be hard to see but they have a little bitty black head or tail. I change the water out every morning. This winter has been very wet here and expecting more rain if that has something to do with it. I don't know if any of the chickens eat any or not. What are they, why are they there, and how did they get in there?