welcome - from Spencer NY. south of Ithaca.
If you have some space, plant a chicken-only garden near their yard/coop. I throw lettuce and birdseed out in thier space, water it lightly so it "sets", lay a piece of cardboard over it all and wait a few days. when i take off the cardboard there are tons of little seedlings erupting and then i let the chickens have-at-it.
They leave my real gardens along for the most part.
you can also plant climbing veggies on their fencing and then will pick at that too.