Thanks for the suggestion. However, I don't have any lawn to cut grass from. What I do have in abundance are California poppies, most of which have dried and gone to seed. (My landscaping is rather native.) So I gathered up a large wad of dried stems and leaves and put them in the nest boxes, kind of swirly, then added some pine shavings. This might work. The poppy stems and branches might give them some substance to fool around with, but they'll be less able to kick out the shavings--that will provide some softness. I also put some DE in for good measure. We'll see in a month or two what the girls think. As of now, they haven't even investigated the nest boxes. Thanks for responding. Henalaylady