I've never read anything about chickens eating out of boredom. I really doubt they would. And you would have to have a LOT of squirrels to be losing that much food in a week. I have 40 16-wk old pullets and cockerels and they go through 50# in 5 days, give or take.
I looked at the Ware Milling website. Which feed are you using? Looks like the only grower has an antibiotic which is supposed to increase feed efficiency. And the ingredients are sketchy--they must change from batch to batch because all it says is "Grain Products, Plant Protein Products, Grain By-products", which could be any number of things. But to me it seems that there isn't enough variety in this feed. You might consider switching to something else with more variety in grains/seeds. And if the feed you get doesn't contain an animal protein (it probably won't as most mills are catering to people's irrational fears of contracting mad cow or something from their chicken meat and eggs), then add animal protein to their diet. Buy a bag of fish meal at your local feed store and give them a small handful every day. Throw them some freeze-dried mealworms each day. And offer them greens: pick dandelion greens from your yard (no chemicals on the lawn if you're going to do this!) and throw them in to the birds. Give them your fresh fruit and veggie scraps (check online for items they can't have, such as onions).
Hope this helps!
