I have a 50lb. bag of grower feed I've had for just over 2 months (I only have 2 chicks). It has been sealed in a barrel the whole time. I just discovered it is infested w/ thousands of tiny (barely can see them move) peach colored bugs the size of a grain of sand. They must have come in the feed and I've not knowingly been feeding it to my girls all along. What are they and are they harmful to my hens?