I need help:(

[Willowmrh]

So I used to have rats when I was little so I ended up getting more again(5 total) and I noticed one of my younger ones, Ivy, had a toe bleeding she wouldn't let me look at it so I've just been trying to clean it. So I just discovered another one on her other paw! The old one has turned black and I am concerned the nail was kind of sideways so I'm assuming she do something to the nail but I am a little concerned... What should I do?

 

[Fidget]

Obviously take her to the vet if you can, the toe turning black is a major concern. Check around the cage and see if you can figure out if something might be catching her toes.. Since it's just happening to her and not the others, is there a chance one of the others could be biting her toes?