Search the internet, and you'll find about as many opinions on feeding food waste to chickens as you'll find....well....opinions on anything on the internet. Some say "no way". Some say "sure, but only 10% of their diet" (but never specify if that's 10% by weight, volume, or caloric count). Then there are the nuts who say "Yes! As much as you can get and they will eat!" I am one of those nuts.
One of our motivations for getting chickens, in addition to the entertainment value and the fresh eggs, of course...was that they are food waste eating machines! When you have two small children, you generate a LOT of food waste!
We do feed our current flock layer pellet, but supplement with as much food waste as we generate or get our hands on. This includes not just what we generate at home - we have a "chicken bucket" on the counter to collect it throughout the day. But it also includes what we can get from other sources - for example, whenever my employer brings in food for a meeting or lunch event, I get the scraps to take home. What may not look like a lot on the plate adds up in a hurry (see the photo at the top of this post for one "food waste rescue" from the office).
Feeding food waste isn't just something you should do if you're cheap and want to save money on chicken feed - although both of them are true in my case. It's also a great way to cut down on waste going to the landfill - in this case, some of the most environmentally dangerous landfill-bound waste. When food waste decomposes anaerobically (without oxygen) in a landfill, it creates methane, a greenhouse gas many times more potent than carbon dioxide.
Food waste can of course also be composted, which is far better than landfilling it, but by adding chickens or other livestock into the equation, things are kicked up a level.
The chickens convert the food waste into healthy, fresh food (eggs) and nitrogen-rich manure. The EPA's food recovery hierarchy lists "feed animals" above "compost" on the triangle, meaning they recognize the value animals have in recycling food waste.