Need Help Please.

My dad recently adopted a puppy from the Animal Defense League where I am from. She is a female, approximately 7-8 weeks of age. At first she was calm with us and slept all day, I was expecting her to eventually get used to the fact home was here, she and her littermates were found under a shed after a neighbor abandoned them. She is a labrador retriever  mix, she is as sweet as can be, the only problem we seem to have is after we took her to the vet and she was diagnosed with kennel cough and treated. She seemed to develop a nasty biting behavior and our vet has said to clasp her mouth with our hands to tell her no. I have been doing so as the rest of the family as well, she just gets more aggressive as if she thinks it is a game. I am at my wits end I am her primary caretaker outside of 5 hours a day and weekends. I am not sure what to do.

and giving her back isn't an option, I know the shelters are "safe" but I feel bad leaving her.
If you can offer any advice I would be greatful

[ginger899]

This has to be stopped, as what she is learning now will stay with her for the rest of her life, unless checked.
I think she has been taken from the litter too young. She has not learned early lessons which she could only learn with her litter-siblings, and her mother.
Biting is natural for a puppy, and with its siblings and mother, a pup learns how a gentle bite is playful, but a harder bite brings either squeals, or chastisement(from the mother) Usually, when playing and bites get too hard, the other pup, the one bitten, will squeal, and usually that stops the pup biting immediately.

I tried that with the dog I had before (a Jack Russell) When I first got him he was nearly 8 months old, and was still biting too hard. Every time I felt his teeth I squealed like a pup that has been hurt. It did work. He stopped biting hard. He learned how far 'play' is meant to go without it getting serious. You could try that.

[Thomas Dock, CVJ, Vet. Technician]

Ginger is right...this is any important behavior to stop and stop soon.

Dr. Suzanne Hetts, a certified applied animal behaviorist, as written in her book "Raising a Behaviorally Healthy Puppy" to do just what ginger has said.  In fact, in often works to ignore the behavior and walk away from the pup.  After she has calmed down, go back to play with her and if she acts "nice", she gets the reward of playing with you.

Dr. Hetts is also available for questions in our Ask the Vet expert forum under the Pet Behavior Forum.