i have 2 female ducks, same age, and when I fill up their kiddy pool, they both get so excited and really hyper...one of the things they do in there is stand on eachothers backs and one will latch onto the neck feathers of the other one. The weirdest part is, the one being stood on and nipped seems to be totally fine with it and even participated in letting the other one get on her back LOL! I make them stop sometimes because the one getting nipped will get her head held under the water and I don’t want them to accidentally drown eachother (they seem to only do it during bath time). They also do it equally to each other, it’s not just one doing it to the other. What does this mean?