Mine definitely prefer a bowl over the nipple, and I think it's just because it's more work to peck the nipple. I'm working now on creating some kind of cup to go under the nipple to catch some of the water that falls, hoping it will encourage the nipple drinking.. the only reason I'd like them to use it is I have an aquarium heater in the nipple bucket to keep the water from freezing, and I'll be going on a week long trip mid February and don't want my mom to have to bucket a bunch of water down to the coop. Anyone know of any hacks to add some cups on the nipples?