You should be able to get alfalfa hay at any tractor supply or feed store. You might find it on Craigslist or in local ad papers like the Penny Saver as well.
The run is looking good. I like WhiteWyan's ideas. A deeper tub filled with sand would make a good dust bath, and they do love to play around with alfalfa hay.
Putting things for them to hide behind or explore is always something they enjoy. Even weighted down cardboard boxes will do the trick...