Did chloe jump up at the kids before she was spayed? Not even to bite, but to jump up and play???
The reason i'm asking is that this could be the progression of that...just like any puppy does with their litter mates they jump about and nip...and I wonder if she sees the kids as just her playmates??? It doesn't seem like it's aggression from what you've said so it maybe play gone too far???
I would think about what the kids 'do' for her...as in do they help feed her etc...wipe her paws when she comes in, groom her etc...just so it is not always 'play' time.
I'm only guessing, and it's hard to guess when you don't see it in action...but just a thought...
I hope you get it sorted soon,