I recently started using a 3 gallon metal double wall fount for my 4 chickens and 5 ducks. I have noticed that the pan that fills with water, where the birds drink from, only fills about a 1/2 inch deep with water. Can anyone tell me if this is normal? I expected the pan to be fuller. I am worried it is not deep enough for the birds to drink from adequately, especially the ducks. I also fill a 1.5 gallon heated bowl every morning to make sure the ducks can dip their heads, but they empty that one pretty quickly so it isn't a reliable drinking water source throughout the day. Thanks!