I feel VERY stupid asking this - but what the heck is Chicken Mash!!
When I made Mash for my chickens I got a pie pan and put laying pellets in it and added a little water and stired'er up and added different treats to it for the chooks?!?!?
Chicken mash=laying mash. Which is the same thing as pellets, just in little crumbs instead.
Interesting idea. I get 40lb bags for $8.50. Whereas litter is $7.90 for 28lb. I could see it being good compost, but how would you keep the chickens out of the compost pile?