I can relate to this one - about a year ago I went out in the yard to find my neighbor kids poking at Pandy through the fence - she was barking w/ hair raised etc. I'm sure this had happened before - but ever since then she nips/bites kids - especially if they are running anywhere near her.

I had her evaluated and he told me that she probably wasn't weaned from the mother at a young enough age ( I got her at 8 weeks, he told me they should be taken at 4-6). Said that the kids aren't the sole reason she's nipping but it doesn't help either. He also said that something must have happened to her as a puppy, like either she was kicked, held too much, pulled on etc. by kids and she remembers that. She is 2 1/2 years old and said that even though it seems like it just started ( which it did out of the blue) since she is getting "older" she feels more confident to bite. He suggested basic obedience classes.