It's been about three days since I put bells on Dazzles collar, and she hasn't returned with any gifts. That maybe helping. However it wouldn't surprise me if she's keeping them in her secret layer since I was getting upset when she brought them in the house. She's a very perceptive cat.
On a side note. She doesn't seem to mind the collar but I take it off when she's indoors. There's no reason it must be on 24x7.