I am not sure if this is unusual or not as this is my first spring with drakes (we purchased the ducklings last year), but the drakes are pairing up to mate with only one hen at a time. I have a Cayuga drake and a Khaki Drake and they will work together to chase down one hen and one will climb on top while the other pins her head to the ground. When the first one is done, the other will climb on top (although the hen usually makes her escape during the transition) Is this normal behavior? I expected they might fight to establish dominance, but I didn't expect them to work together "gang rape" one hen. They aren't picking on one hen in particular, but I am getting a little concerned as we have had two of them come up lame in the last couple weeks. I just returned one to the pen that we crated because she had swelling in one foot, and now another one is limping. This one does have any swelling, but she won't put any weight on one leg and I am worried it might be sprained or dislocated, so she will be spending the next few days in the the crate. Hopefully it will be better by then.