That is a wonderful idea, LittlePuffyTail. The rescue that I work with does this every year for the buns in 10 shelters in the Bay Area, plus all of our foster bunnies. We have 350 bunnies this year. As someone suggested, we give each bunny a paper bag with treats and toys in them. My daughters and I are making the hay rolls that BinkyBunny suggested; these are cheap and fun to make. We also give small treats, like the little heart cookies from Bunny Bytes and hay cakes. Each bunny gets a toy of some sort too, like a little jingly cat ball or a barrel toy. How good of a sales person are you? Would you be comfortable asking any local bunny oriented stores for donations? Maybe a feed store could donate horse cookies that are rabbit safe, that sort of thing? Even just a bag of oat hay, tied with a raffia string and a bunny cookie or a piece of dried fruit inside would be welcome, I’m sure. Just be sure to clear it with the shelter staff first.
The bunnies go wild for these things, it is pretty funny to see. Have fun with it! Some pictures of our program last year can be seen on our website.