They look mixed to me, but at this age, no way to tell as others have said. I see no reason to spay the bitch, the owner should just be more careful. If your intentions were to breed your bitch, she can still have puppies down the line that are purebred. If that was your intention, keeping a pup out of this litter would not be a good idea.
Heidi Ho, Odie
Joy-Joy, Bear Cub, Hepsi-Pepsi
Cujo2, Karma Chameleon
Ramona the Pest, Kojak -- who loves you baby?
Tiny Tinnie, Susie's Uzzi, Kaiah -- The Baby Monster.