MHC

[WannaBeHillBilly]

It's a good sign if they don't use the cave: Ducklings are very smart and they have already figured out that this square thing gives up heat. They will use it when they need it and as @Miss Lydia said, in the end they may spend more time up on top of the cave than inside:

 

[Quackattack717]

This is how my brooder is set up. The babies seem to spend most of their time over where the food & water is as you can see by all the poop. There isn’t much poop else where besides in the chips right next to the water corner ( I think that’s where they sleep?) I worry because when I get home from work their bellies are all wet from being on the pads that are wet from their water mess. I’m only using the pads until their feet are big enough for the cookie cooling racks that catch their water/food mess but with the pads they’re getting very wet because they’re deciding to stay over there.

I see in your picture your water is close to your cave. Do you think they want their water closer and then maybe they’ll use it? They gotta be a little chilly. It’s getting pretty cold at night and if their little bellies are wet it’s gotta be chilly!