I feed quite a lot of "treats" but I make sure it's varied. I probably split a handful of mealworms between 15 chickens a day. or every other day. I give mine a mix of corn on the cob, tomatoes, various seeds, etc. I try not to give too much cracked corn, but they love it so much I probably feed slightly more than I should. I love it because I can throw it down and they will stir up the litter for me
I also go outside and dig up a plot of grass/dandelions for them. I keep forgetting to put the dirt back when they are done foraging off of it, so I'm going to need to fill in a few holes soon! Actually, I just need DH to get off his lazy butt and help me finish the coop! I swear my hens will be LAYING before he does it!