I started making suet blocks for the wild birds years ago. Finally hit me one day, gee, I bet the chickens would like them. Duh!
I get beef fat scraps from the local butcher, (cut all the lean off, it will rot), melt as far as they will melt and add birdseed, oats, dry cat chow, cornmeal, stale bread, scratch feed, just whatever leftovers are around the kitchen. Chill in an old cake pan and cut into blocks. An old piece of chicken wire or hardware cloth makes a cheap holder. I hang it a bit high, so they get some exercise while pigging out. They love it and they get exercise as well as some extra fat during the winter. Don't do this in the summer, or you'll be raising flies and roaches. The suet mix freezes fine, so I do big batches. The fat stinks while melting, so don't do this when company is coming. A crockpot type cooker works well for the melting, if you do it stovetop you need to be their every minute- major fire hazard!
Sometimes I make popcorn balls, rolled in birdseed, and they LOVE those. (So do the squirrels- we are a certified wildlife habitat, too. )
We have some old lumber and brush piles around here. I sometimes "direct" the chickens over there, then knock the pile around. They LOVE the bugs, and will fight for a roach!
The whole idea is to figure free or cheap ways to keep the chickens busy and warm. Just look around you, you probably have tons of potential toys, food, etc, then make it safe for them. Gotta think like a chicken !
