Saved 2 baby field mice

Question
My dog picked up a mouse nest and 3 little ones fell out. They were about a week old. They had a tiny bit of hair and their eyes were closed. I watched the youtube videos. I lost one and felt so bad. I have been able to feed and take care of the other two. They are alittle over 3 weeks now. I think I have a boy and a girl. They are in a 35 gallon tank with tons of toys and a nice nesting area. Today was the 1st day I turned off the heating blanking and them seem to be doing well. They like an old dish cloth I put in their nest. I am hoping they continue to do well as I have grown very attached to them.
My 1st question is my little girl seems to have very thin hair toward her back end. Her skin has no scabs or sign of injury. It almost reminds me of alophcia, but not totally bald. Just thin hair in which you can see her skin.. I think I read somewhere that this is normal and it will grow back. When they were little and in their nursery tank I would bath and dry them. I thought they were now old enough to do this for them selfs. The male is nice and fuzzy... Any suggestions? Also, they seem to scratch but no an abnormal amount. Figured this is part of their mouse thing is that correct?
My 2nd question: I have decided to keep them as pets. Like I said before I think I have a male and female. I would love to keep them together as thru my reading I realized they enjoy having one another. I am having a hard time telling for sure. The one I refer to as my little girl is smaller than the one I think is a male. At what age will I see testicles if they have them? Also, at what age can a wild field mouse become pregnant as I dont want babies? If I do have a male and female can you tell me about neutering a mouse is it painful for them? Does it cost allot of money? Also, will a small animal vet even treat a wild mouse? I heard I can get in trouble for even having them. Any info you can provide would be greatly appreciated. Thank you for all your time in helping the little creatures most dont even consider worthy of life...You are great people..

Answer
Hi Kimberly,

Thank you for saving the little fellows!

Losing fur is completely normal for hand raised mice. You didn't lick them like a mouse!

Unfortunately male field mice aren't as noticeable as house mice. If you are on Facebook and friend me (Natasha-Mouse Millikan) I would love to bring you into a pm thread with other people with experience raising orphans in order to help the next person better. Also you can post their undersides and have people help. If you just send me the photos I can show people and get an opinion in case I can't tell. Only females have nipples though, but they are hard to see.

I would separate them by 4-1/2 weeks. Make field mice can live together, which is wonderful. Neutering isn't painful for anyone considering it is under anesthesia, but good luck finding a vet who does it at all, let alone has a good success rate. Laws differ in different states; i have had people write to me whose vets were not legally able to see the animals. Others have no problem.

The only vets who will see mice at all are exotics or pocket pets vets. If you need help finding one either write back or on Facebook come to my mouse and rat site Rats are Awesome and we have a couple of vet finder links in a document under 'files.'

Squeaks n giggles,

Natasha