We feed the bunnies sriped sunflower seeds. It is a good vitamin source for them and the oil helps their coats. Okay, the REAL reason is that they LOVE the seeds. We put about a dozen seeds on top of their grain along with a tablespoon of old fashioned oatmeal. Not all the seeds get eaten, some fall into the drop pans or otherwise make it to the manure pile.
The sunflower seeds took root and lined themselves right up. You can see what is left for fall foliage in the photo below where the woods border the field. And barely make out our stone wall at the tree line. If we had TRIED to grow the sunflowers, it likely would not have happened.
Meanwhile... back at the manure pile.... I threw out a small round watermelon in August. There is probably 15 feet of vine back there with lots and lots of flowers with some watermelons started. They won't beat the frost unfortunately. I know what I'll do next year, just throw an assortment of seeds on the edge of the manure pile and let 'er 'go! One late November I threw out a few of those cute little ornamental gourds you decorate with for Halloween and Thanksgiving. The next year we had a gourd-kingdom out there. I was giving them away at rabbit shows, for library children's activities, trading at local farm stands for other produce. I counted about 700!