I don't have my chickens yet, but have been following this post with great interest. I found this by accident when planting new grass around my almost done coop. Its called Ultra Nu- Straw by Amturf its a double shredded straw with a bonding agent. I was a little concerned about the bonding agent so I emailed the company.They replied and said it would be safe for chickens the bonding agent is a product used in making ice cream.This stuff feels very soft for being straw.You can see this product at Amturf.com. I found it at True Value hardware for about $10 a 2.5 cu ft bag
Vinnie
Vinnie