Ive been using one for a couple weeks now and all do fine with it. Except one. I got her a little later and she was sick so I kept her separate until she was well. When I first put her in with the others, she wasn't using it at all. I was giving her water from a bowl because I was worried about her getting dehydrated. I figured she would see the others enough times and get it. Well.........she gets it now, but she violently pecks at it and Im afraid shes going to hurt herself on it! The others gently push up on the ball. Hopefully she will get better at it because I was not happy cleaning poo out of the waterer 3-4 times a day!