Hi Michelle and welcome to the Forum.  

 I only have seven chickens but they are real characters and good layers.  I do give mine all sorts of fruit and veg, including apples.  I noticed they liked them when at my last house I had apple trees and I gave them some windfall.  They also like tomatoes.  I also give them rice and pasta, although some one told me recently that although they love rice, it has no nutritional value for them.  They love lettuce too.  Mine are not loose in the garden so do not have a lot of green matter to eat around them.   Boiled potato skins are popular too and of course any kind of bread.  This all supplements their mixed grain and layers mash.  Mine do not seem to take to the pellets.   Not sure they should be having cat food, especially if you give the eggs to other people.  I read somewhere they should not have meat. I could be wrong though!