I've been battling lice with my 4 hens for a while. I dust them with sevin every 2 weeks and clean the coop out weekly and sprinkle sevin all in the shavings...I just went to collect eggs earlier and saw 3 lice crawling on the wall inside the coop all around the sevin dust! What the heck do I do now? Will there always be a few lice? I don't like those creepy crawlies on my birds!