I really appreciate all of the responses. We've just been getting more and worried about Bailey because he doesn't just nip for a minute and stop - sometimes if we try to reprimand him, he retaliates & tries to bite more, rather than getting startled. Nothing seems to scare him, and our vet feels he shouldn't be biting at this point. We think he's about 12 weeks, but we don't know how old he was when he left his litter since he's from a puppy mill. We're just hoping we're able to stop it soon, because we can't have a dog that bites! He actually bit the assistant at the vet today.
:-( Hoping he learns fast! In other news, he learned how to "sit" in 2 days, so we know he's selectively trainable!
Sounds a little over stimulated /overwhelmed...what is going on when the biting starts- are you on the floor playing or holding her trying to pet her,or does she just walk up to you and start gnawing on you ? Look at her body language. Gentle hands are important, take a deep breath, you are smarter,and bigger than this pup and you have to show her how to use her mouth which are kinda like our hands to her. Don't let her chew on your hands. Gently place a chew toy in her mouth whenever she tries to mouth you. If she becomes a snapping machine walk away from her and do something else, no interaction. No alpha putting the pup in it's place type stuff, you are not a dog. Make sure she gets some down time. Try fetch or a big ball for her to herd to tire her out . Hang in there. Sorrry to refer to Baily as a she-I have a female so just seem to think that way...

She is not an aggressive dog but her "biting" did transfer into stealing (unfortunately she became obessed with stealing hats from small children
) She is just over a year now and much more settled thanks to good training advice and lots of work our kids have a wonderful companion. 