I have 8 ducks total. 2 pekins, 4 khakis, 1 buff and 1 blue swedish. The 2 pekins and 1 buff are around 2 to 2 and a half months old. My khakis are around 4 to 5 weeks old. One of those khakis is biting at the older 3. Lots of space for them to move around. Does it in the pool and when they eat...