Suet is the hard fat found around the kidneys and heart of cattle and sheep, while regular fat occurs throughout an animal's body and is obtained by trimming beef lamb or pork cuts. We can buy it at the grocery store sometimes or we get it free from the butcher shop.
Avoid using bacon dripping, too much salt.
I don't feed suet to my chickens but feed it to the wild birds, woodpeckers, chickadee's, nuthatches and blue jays.
I guess a bit for a treat would be okay, but I wouldn't give too much.
When I make it for the wild birds I add peanut butter, shelled sunflower seeds, rolled oats, wheat germ, nuts, small hand full of grit, I melt this on the stove and mix real well then freeze it in containers for later use. Suet with chicken scratch sounds great for a small treat. I use those bags that you get tomatoes on the vine in, or onions bags if they aren't too big. Wonder how it would work if you hung some in the coop for them to pick at?? You have given me an idea!!
hope this helps,