BAD Breeder. Is this cancer?

Hello guys,
I am new to this forum. I wanna give some info first:
I have 3 rats myself (2 males and 1 female, in different cages) and today I got 2 new ratties from a breeder I came across on the internet. One hairless (female) and one albino rat (male). Yesterday I texted the guy and told him to please send the rats in seperated cages as I am NOT a breeder and I don't want unexpected babies. He said "sure" but sent them to me in the same box! I am now also sure that he had these ratties in the same box even before I got them too. Plus he put pine bedding in their boxes. Anyway since hairless female rats have problems lactating I really have no idea what to do if she gives birth :help:
Both rats are really scared and shy but after spending some time with Casper (the male) he got used to me and he even likes to be pet. I tried to introduce him to my other males in the bathtub but he bit one of my rats, there was blood so I took them back to their own cages.
Now comes my question:
It is almost impossible to pet the female. She kept running away and tried to bite me. (Not like attacking, she kept opening her mouth) so I thought maybe she was hungry. I put some dried food and fruit in the cage and GOD she ATE like a bear! It has been an hour that I gave her food and she is still eating nonstop!! She is very skinny compared to my other hairless rat so my guess is that the breeder barely gave them any food. But the male one seems pretty huge so it may be that he ate most of the food and the female one didn't get to eat much.
The big problem now is, she has a HUGE scar on her back which is dark and looks like a scab. Is it possible for rats to have skin cancer? Or is this just a scar and dried blood? Since she has claw marks all over her hairless body it is possible that Casper scratched her. Or maybe even attacked her? I thought if he was that aggressive towards my rats and bit them it is possible that he may have bitten the female too. Any ideas?
Thanks a lot!!!

I can't really tell from the picture, sorry, but is just looks like a healing scab from a big cut to me. One of my hairless rats had a ton of scars all over her body too from getting in scuffs with other rats.

I see, thanks for your reply!!I really hope it is a scar.

That looks like a really old massive gash and it's healing over. But if that was my girl, I'd get her on enrofloxacin asap. (baytril) And also, Oxbow rat food is the best for them to ensure they get all the nutrients they need right now.

That is what I think too, an injury that is healing. I too would get her on antibiotics such as baytril and watch her for signs of infection.

btw, the recommended diet for rats is a good block with low protein levels (Oxbow Regal Rat or Harlan Teklad 2014 are the best) and daily vegs and occasional healthy treats like a piece of fruit, cooked grains or cereal (like quinoa or oatmeal or 12 grain cereal), organic pumpkin seeds etc. ........ and there is a forbidden foods list http://www.ratshackforum.com/forum/showthread.php?t=590

hope she is soon feeling much better

Thank you both SO MUCH, you have been a big help! Update: Today a part of the scab is fallen off and I can see healthy skin underneath. I am now positive it was a big scar. We are putting her on antibiotics today.

My guess is that she was in with multiple rats so definitely may be pregnant. The good news is most likely she's not a genetic hairless and is more likely to be a double rex who don't have problems with lactation. Poor little lady That is a heckuva wound someone gave her

If she is pregnant, then it might be a good idea to hold off on antibiotics unless she seems to have an infection .... and some antibiotics are likely less harmful for pregnant rats - Check with your vet and you can also ask Lilspaz68

Thank you so much! I feel so relieved to hear that lactating most probably won't be a problem Now it is time to get her to gain some weight before she has to take care of babies xx

She doesn't seem to have an infection, but the scab came off before it was heeled so it is bleeding again I am not sure if she is picking at it. The wound is deeper than it seemed to be at first. Would it be a good idea not to use antibiotics but clean the wound daily & put some ointment on it?