that's a great idea, I love free. However, bark is a great place for pest to live--mites,etc. You might want to consider de-barking the limbs first.I plan to use two natural tree limb roosts about 3" - 4" in diameter and 8' long. I was reading a thread on here a few months back where a BYC member mentioned they ran out of $$ towards the end of coop contruction so instead of buying a second 2x4 to install a second roost, they just used a large tree limb instead...all the chickens preferentially roosted on the tree limb...so that tells me they like them better. Plus, where we live, there are tall, skinny trees everywhere and the best part - they're free.