Sudden aggressive behaviour from one duck

[DukesDucks]

I have two coops with Muscovy ducks. In one coop things went fine despite 3 ducks sharing the nest. In the other coop, only 1 of 4 ducks went broody. There are 3 other ducks and a drake in this coop. Because of past experience when ducklings were killed, I take the eggs as soon as there is external pipping and finish them inside.
She has only one egg left because I choose to give it an extra day but think now it is dead. Tomorrow I will remove this egg and remove the nest. This afternoon she has gone crazy. She is aggressively chasing, pining down, and has pulled feathers from one of the other females. Seems to be only aggressive towards this one. They are sisters so have always lived together.
Any suggestions as to cause and what I should do would be appreciated. I can't move either one to the other coop.

 

[Miss Lydia]

I have had this with my broody Muscovy also. I have it set up now where I can close the part of the coop where my meany is sitting. [No eggs] In the past when one gets like this I have a small coop that I have used to put her in time out over night and that usually takes care of it. It started out this year where she was going after my 14 yr old female Muscovy and I will not put up with that. She can chase everyone around outside they all know how to stay out of her way. But I won't tolerate her or any other them doing this once closed up for the night.