Now before I go and get anyone riled up about this question, let me explain. I was at my nephew's birthday party last night and we got to talking about our chickens, dogs, ticks, DE, and so forth. I was trying to give some simple advice to my BIL on how to get rid of ticks on his dogs, since they've had such a bad time with them this year. Well my nephew chimes in and says that cedar works really well to repel ticks. I agreed that it does work well for dogs. Then my nephew says it works great for the chickens and their bugs also. I about fainted! I then told him that cedar was very bad for the chickens and should never be used. He then announced that he'd been using cedar in his coop for over a month now and the chickens haven't had any adverse affects from so he didn't believe me. Well I'm standing there, mouth open and trying to figure out what to say. He then asks where I had heard such a thing. I explained that everything that I had read here on BYC says that it is bad for chickens and could damage their respiratory systems. He then just sneered and went on his merry way. I then felt under educated about this whole cedar thing. I'm just one who reads a lot on how to care for my animals and if I read that it's bad, then I take heed and don't ever do it. What in the world do I say to my nephew? Why else is it bad and has anyone ever experienced why it is bad? Just curious.