I have heard of this "Flock Block" but it sounds like junk food to me. The chicken/duck equivalent of Cheetos. I have heard ducks don't mind the snow, but what can I put in their enclosure that will keep them entertained on days even they don't want to / can't venture out? I especially like D.I.Y. / Homemade things. They do have a small pool in there that I plan to keep running with a bird bath heater. In summer I have made the layered frozen kitchen scrap treats, and that has worked well.