Thanks! Cedar is nasty stuff. It kills reptiles (damages the liver) and I believe it does the same thing for birds. My only concern about my aspen is that it is cut into slivers. Soft slivers, but still I worry about young animals getting it stuck in mouths. I can get kiln dried pine in soft, curly shavings if that is better. I saw someone else say that about medicated feed as well.Your wood chips will work fine for your chickens. The only type of wood chips that have any kind of warning on then, are cedar. As far as I know the problem with cedar is that they are to aromatic. Do do know that there are members that have used cedar with success. At this point, I wouldn't use them. The cedar is more expensive, and it's not worth the risk.
I would recommend that you use medicated feed for at least the first 2 weeks of your chicks lives. The chicks immune system doesn't kick in until after they are 2 weeks old. Chicks are prone to pasty butt at this point. I have lost too many chicks over the years to risk not using the medicated feed.
Jennifer