Why did my ****** attack her 2 week old puppy?

My ******'s puppy's are 2 weeks old today. We went out for a couple of hours last night to baby sit for family. When we arrived home my ****** had trashed the kitchen&was covered in blood. I thought she may have pinched a tin of cat food off the side and cut her mouth, but the blood was on top of her nose. I got my boyfriend to quickly check the puppys&what we saw totally devistated me. She had bitten the face of the dog, his face had a large gash from his eye to the side of his face &he had a slash down the other side of his face near his eye (luckily missing it) &a few puncture wounds. He was still alive luckily just very frightened. I took the two girls away from mum to be safe&rushed the dog to the vet. He said not to stitch the wound because we will be closing the eye up&locking in infection he had a jab of antibiotic, pain killer&gave me 2 injctions to do today, also some stuff to rinse his wounds with. I cant understand why she did it she's ben fab with them all this time...cont