Can depend on when they chip it...if they cut the branches and grind it up when tree is in full leaf, the mix is going to be wetter. I assume they bring it to you when it's just been chipped.
If you've got a good place for them to dump a load, good to let it age for a few months before adding to run, fresh chippings can be pretty 'wet' and host massive mold growth in amounts that can be toxic to the birds.
I usually let my grass grow pretty long and cut it before it's going to be...
So like bagged mulch from the garden store...
.....or wood chippings from tree trimmers ....
..or..something else
The larger tree chippings I use seem to last a long time, which is good as they are the best base ingredient for decomposing the poops...you just have to keep adding stuff to keep...
Well, we hope so, but often that is not the case, depending on how it is harvested there can be plenty of grain left in a bale of straw. I have lots of wheat growing out of my straw mulch on the garden.
IIRC, hay is cut before it goes to seed, the leaf part is what is valuable as feed.
....as well as air/oxygen, to keep the mix aerobic rather than anaerobic(when all the nasties can proliferate).
Ditto on the Deep Bedding vs Deep Litter.
Here's good another post on DB vs DL:
http://www.backyardchickens.com/t/1075545/can-i-do-deep-litter-method-with-this-coop#post_16440037
I...