When to integrate new female ducks

[Moments]

We lost a duck to a fox :-( I think they were too big for it to keep a hold of. It attacked 3, but one had too much damage and passed away. The the other two were brought to the vet and are doing well. I was surprised to see the coons only going after their food but thankful. Within the last couple days we've seen more hawks than usual and they're flying lower quicker than they were.