I fill it to the edge of the hole, lower for water. They stick their whole head in, pick around, not too messy. The further down the food line gets the less they spill though, but I keep it filled high regardless for the bantam ( they still spill less than an open tray )
With taller birds like geese maybe you could put the holes in the lid.
With taller birds like geese maybe you could put the holes in the lid.