Dog bleeding when eating milk bone?

I adopted a rescue dog and I gave her a milk bone, there was a little bit of blood on the bone. She was abused before, I'm pretty sure that the previous owners didn't take care of her dental health. I know that when humans don't floss they bleed easily. Is it something bad coming from a dog? or should I call a vet?
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She may have cut her teeth on accident. I don't think that feeding her Milk Bones is all that great they are really unhealthy, I suggest you feed her raw hamburger meat.
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