Where to get more veggie scraps for compost?

I would like to start ramping up my compost production and create a system that can provide some food to my chickens as well. My problem is, I don't produce a lot of fruit/veggie waste right now. My main sources of compostable material are grass, weeds, and cardboard.  My chickens already have access to all the grass/weeds they can eat and I'm pretty sure they won't be interested in cardboard...
My thoughts right now are to go to a small non-chain grocery store or maybe restaurant and ask them for waste produce. Anybody out there have any luck with this approach? Any other ideas? It just seems like such a waste that the chain grocery stores throw out so much food just because of liability. I would even sign a contract saying I won't sue!

I get mine from a local college's cafeteria.  They were actually happy to do it so that they could brag about being green and sending less stuff to the landfill.  That's where I get coffee grounds also.  About a 5 gallon bucket full every other day.  Surprisingly, my bantam chickens looooooove the red onions in the vegetable waste taken off the salad bar.  They go nuts over them and will fight for them.