I have 4 chickens, they are two years old. I just got a nipple waterer. I can't get them to drink out of it. I tried tapping the nipple, holding them up to it, and holding them up and putting their beak on it so water comes out. When I put their beaks on it, they drank, but as soon as I hung it back up, they wouldn't touch it. I put my vacation waterer under the porch just so they could get water, but i don't want to have to use that one. Does anyone know another way to get them to drink out of the nipple waterer?