Think of the eggs as a gift from your hens to you. You give them lots of good stuff and good care/love, they give you precious tidbit for you to enjoy. As far as things for them to enjoy, there are treats you can make, you can invest in some things that are about parrot size, hang some food items, maybe even come up with a chicken-safe pinata that they can peck at with treats inside. The pinata would have to be something that they are willing to go after, so maybe have little treats on the outside to encourage them to peck at it, and a bonus of treats inside for when they do get it open. You can also make ladders out of scrap wood or pallets, or look around at garage sales for items that are big enough for them to climb on, but make sure that they are not able to be dismantled by persistent pecking.