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The reason she doesn't want to feed her puppies is because dogs wean their pups starting around 3 weeks of age and usually by 4-5 weeks of age they are fully weaned and eating dry puppy food. At this point they should be offered a gruel of puppy food soaked in formula or goat's milk. Over the next 2 weeks the amount of formula added to the puppy food is decreased and fresh water is offered. Puppies should be eating puppy food by 6-8 weeks of age and stay on puppy food until they are a year old at least.
As for her nipples, if you haven't been cutting the nails of the puppies, they have likely cut her breasts and nipples. In addition, the pups have teeth and likely have been gnawing on mom's nipples as well. This is quite dangerous as it can allow bacteria to enter her milk ducts and lead to mastitis. Mastitis is generally first noticed as a swelling and inflammation of the breast. While it is easy to treat, it can be deadly if not treated quickly. Mastitis is caused by bacteria entering the nipple and gaining the upper hand leading to infection which often can enter the blood stream and thus infect other parts of your female as her immune system is already under the stress of having pups and nursing.
Here is a site on Mastitis:
If she has symptoms of mastitis, you will need to have her seen by your vet. Definitley stop the pups from nursing on her. You can do that by taking a childs t-shirt and cut it at the armpits and use the bottom part to put around her middle and keep the pups from nursing.
Those pups are more than large enough to be eating puppy food. If you do not have goat's milk or puppy formula, just put food in a bowl and fill it with water and let it sit for several hours until it is puffed out. I'm certain the pups will quckly learn to eat that food in just a day or so.
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