My female dog gave birth to four puppies. They are now seven weeks old. (I AM TRYING TO FIND GOOD HOMES) ANY WAY THE MOTHER DOG NOW KEEPS GROWLING AT THE PUPPIES, she has not fed them since they were four weeks but up until now she did not seem to be bothered by them but now she seems to growl at them a lot and she is never left unsupervised with them. I really wanted to keep one but if she is really jealous of them them it could be difficult, any advice would be welcome.
Thank-you.

It time mom was separated from the pups anyway, they need to get used to not having her around anymore for when they are re-homed.

When exactly does she growl at them? Are they trying to feed? Or just play?
Have you had her with one puppy at a time or just put her in with all 4 of them?

A lot of times the mother may growl or even nip at them to tell them they have done something wrong, if they are playing to rough with one another or her. It's true that they should get used to not having mom around, but it is also CRUCIAL that these pups get properly socialized or they may have issues with aggression later on down the road. They will learn the most from their mom and siblings right now. This is also the time when they learn what the "alpha dogs" place is.
I have been told that a mother dog won't take care of the pups if they have hookworms. Also I've heard about this happening if for some reason mom doesn't have enough milk. If she isn't producing enough, then you may need to increase her caloric intake and hand feed the pups to take the pressure off her. Another reason could be infected mamory glands, extremley painful for mom! Has she been to the vet since the pups arrived?
From the age of five weeks, the mother teaches her puppies basic manners. They learn to be submissive to her leadership and what behaviors are acceptable. If necessary, she growls, snarls, or snaps at them as a form of discipline. When weaning the litter, for instance, the mother will discipline her puppies so that they will leave her alone. Because the mother disciplines them in a way that they clearly understand, after a few repetitions, the puppies will respond to a mere glare from her. If a pup has not learned to accept leadership (and discipline) in its early interactions with dogs, its training will be more difficult.
Also (Now this isn't gospel, but it's a good rule of thumb to go by) Puppies that are removed from the nest too early tend to be nervous, more prone to barking and biting, and less responsive to discipline. Often they are aggressive with other dogs. Generally speaking, a puppy taken away from it's mother and litter mates before seven weeks of age, may not realize its full potential as a dog and companion. To maximize the mental and psychological development of puppies, they must remain in the nest with their mother and litter mates until seven weeks of age.