Mine loved my jalepeno plant!!!LOL! I guess they would love any pepper plant. They also love love loved my tomatillos that fell before ripening, which is interesting because they DON'T like tomatoes. Anything that you plant that needs to be "thinned" is great for chickens. We gave them the thinnings from our carrots, beets, radishes, turnips, and others. When we are ready to replant, we let the hens in to "clean up". They eat excess bugs, rotting leaves, and they do their scratching which does wonders for the soil!! As does their droppings.
Greens!!! Plant greens. Chard, lettuces, and such. Great calcium source for them and they love them.
Also, grass. I don't know if you want that, but grass is so good for chickens and they love it. You could plant clover type grass if you like that. Mine also come up on my patio to eat my cape honeysuckle. They love it. All the lower branches are bare. Would be a nice tall plant in your chicken garden. They are very hardy and the blooms are edible, too.
Have fun with that!!