I picked up one of my 'old' girls today cause the side of her face is a little swollen. I think maybe she got stung by a wasp or something. Anyhow, since I already had her in my lap, I gave her a once over and... YUCK! These little bugs were darting around her vent area! I was so surprised and kinda angry. I thought I was doing everything right. Their hen house has a dirt floor that I rake and shovel a couple of times a week. I dust with DE once a week. All of their nest boxes have clean shavings with DE sprinkled in them. They free range on acres of grass every day.... What did I miss? So I checked all of my other older birds and couldn't find any more bugs. Did a spot check on my 5 month old chickens and none of them had it. Finally did a spot check on my 2 month olds and none of them had it. (I didn't check my 2 ducks...) I am perplexed as to why this one chicken had the bugs and no one else has them. Tonight I raked the coop out, dusted it with seven dust and dusted the nest boxes. Also dusted all my old chickens liberally as well as several of the other chickens. I'll try and find some orange oil to treat the wood in the building. Should I treat everyone with Ivermectin or Valbasin? Does that treat lice? Do I need to dust everyone again in a couple of weeks with seven dust? Should I incorporate seven dust in my cleaning routine? Help!!!