Hi all, I'm new to BYC, I bought two female Muscovy ducklings last summer and they have been the cutest things. Friendly, loving, loyal, however they are now 20 weeks old. One of the ducks has been shivering and then trying to bite either my back or the other duck's back. When ever I turn she puts her beck out and tries to tackle my back with her beck. She also does this with the other duck, but the other duck hasn't done it to me before.I'm wondering if this is normal duck behavior and if she will only do this when shes sacred.