I take it you're already locked into a poured slab. Why not consider a raised coop? These are better in my view as far as air circulation, predator control, and the ability to utilize additional space not afforded with a slab foundation. Chickens adore hanging out underneath raised coops, especially during the heat of summer.
Both raised coops and slabs can accommodate any sort of coop bedding material. I am using sand in both my raised coops and runs. I've found the sand acts as a heat sink, warmer in winter and cooler in summer, as well as ease of cleaning.
Both raised coops and slabs can accommodate any sort of coop bedding material. I am using sand in both my raised coops and runs. I've found the sand acts as a heat sink, warmer in winter and cooler in summer, as well as ease of cleaning.