Oh good to know! Gosh I am so torn. Maybe what I'll do is put a thin layer down in the run and let the sun beat on it for a week or two before pudding any more down? My run gets a lot of afternoon sun.
The only other place I have found to get non-cedar mulch was a garden center, but they charged $90/square foot vs $15/square foot for the tree mulch from the tree service. That's a huge price difference!
The stores here sell bags of pine shavings pretty cheap. Not sure how big your run is but most people leave the plain soil along with any grass/weeds. The birds really like to have contact with the ground to dust bathe and scratch.