Oh my goodness do they love meat. Whenever we eat t-bone we throw in the bones and the velociraptors get to work and pick it clean. They also love chili. Remember, they can't taste spice.
Never thought of chili! We have a dog, so she gets almost all of the table scraps, though she'll have to do without the chili now. The girls can have it and I can have a gas-free dog and avoid the bad air asphyxiation!
I give fruit and veggie scraps; watermelon rinds in the summer are the best. When we first built the coop and pen, I actually planted herbs in the pen surrounded by a wire cage so the girls could eat the leaves without destroying the plants.
I have a metal food dispenser (as from a rodent habitat) mounted in the pen in which I keep a steady supply of crushed oyster shells. It's easier to fill that than to mess with egg shells.
Apparently I feed them wild bird suet, too.

I had a feeder hanging low to the ground and the girls discovered it. I had fun watching them stand on their tiptoes to reach it until one girl strained her neck muscles. Luckily she recovered well, but I lowered the feeder after that incident.
My girls free range during the day, though the pen is always open so they have access to clean water and layer pellets. I'm always a bit surprised to see how much feed they consume even though they have access to the whole yard. Now that I think about it, though, I have seen the dog eat their feed pellets, too. Weirdo.
Like a previous poster, I give the girls leftover bait. They don't care much for worms, surprisingly, but they *adore* crickets. Two or three times a summer I'll even go get a bag especially for them.
I do give them a quantity of scratch grains each morning when I free them from the coop. When I open the pen door the girls think I'm the Pied Piper. I have my own personal feathered entourage as I walk around to the shed side to get the grains. It makes my day to hear them chattering away. "Hey, good morning, big tall chicken. Where you got the goodies stashed? We're right here, supporting you."
"Oh, girls! She's getting the good stuff. Oh man, oh man. Here she comes. Get ready. Oh, my gosh! It's raining food from heaven! Hey you lazy bones in the coop; the good stuff's here!"
"OHHH!! Wait for us! We're coming!"