Here's what my suburban hens enjoy ~
* red cabbage, either whole or wedges (but for whatever reason they don't touch it if I hang it up)
* pumpkins, whole or halves
* romaine hearts
* green or red leaf lettuce
* acorn squash halves
* kale leaves
* cauliflower
* broccoli
I know some folks recommend against giving hay to chickens due to potential crop issues, but I toss some fresh, rough-cut STRAW (not hay) in the runs and throw scratch on it, and the girls love to dig through it searching for their corn.  They will dig through a block of straw for hours!  I do dig it all out every couple of days and strip the run down to the floor, though, and mucking out may not be everyone's cup of tea.
I have also tried redhen's recipe for the flock block, and that has been a big hit.  
We put several perches and chook shelves in the runs to give the girls more use of the vertical space, and they put them to good use.  In the main run we also made a crude "stool" which also has a vertical plywood panel on one side so they can hide under it and take dust baths.  I keep the DE-dirt refilled under it, and they love taking their lady hen spa treatments under it.