mother dog growls and snaps at newborn puppies

Question
we have a 1 year old chihuahua who had her first litter yesterday,everything went fine and after they were born she nursed them for about the first 2 hours,after that she started growling and snapping at them,she stopped feeding them and all night kept bringing her toys to our bed,whining and just going crazy,my wife has been hand feeding the pups and the mother will check on them and clean them but refuses to feed them.we put her in her cage with to pups to encourage her to feed them which she is but she still wants to growl and snap the whole time,anything you can advise would help.my wifes exhausted and cranky.
thank you

Answer
Mark,
I am sorry I answered this days ago, I guess you didn't get it.
It sounds to me like she has sore nipples.
It is painful to some mothers to nurse a litter.  Try petting and distracting her while the pups are nursing.  Even giving her treats.  Make sure no nipples feel hard or solid to the touch.  If they do, try to squeeze (gently) some milk from them...and make sure a pup is always nursing on these nipples.    
If you see any other color coming from the nipple except white, get her to the vet immediately
also if you cant get the milk to come out of a solid or hard nipple, take her to the vet.
nancy