Why? They're likely eating lots of other bugs that might actually harm your chickens. Besides...they're free chicken treats. But I do understand crazy fears...mice are my downfall. I feel like one of those women from a cartoon if one of those little poopmachines takes me by surprise, standing on a chair holding up my skirt. I don't mind them when they're out where I can see them. lol I think you'd be fine to paint/spray the inside of the coop with Sevindust/permethrin. Just let it air out good before you put the birds back inside.
