Baby field mouse in our care

Question
Hello.
 We live in CT and on Mother's Day we found 3 baby field mice in our yard (with no visable nest) and took them in.  They appear to be between 2 & 3 weeks of age. We have had them in a glass tank and feeding them bread soaked in cow's milk and they have been doing great.  They are walking much better and are becoming pretty playful.  Today I gave then some bird seeds and they are eating it. Yeah!
 I told my sons that our goal to take care of them until they can fend by themselves...but my question to you...is that possible if I am providing food and water for them....  Would they have a fair chance to surviving on their own? I was thinking that we would release them when they showed that they could drink water and eat seeds.....is that realistic?

Warmest regards,
Jenna

Answer
Hi Jenna,

Wild mice have very strong food-finding and predator-avoiding instincts that aren't likely to go away from a little help in their youth.  Once they are eating normally, playing frequently, and able to care for themselves I would absolutely release them again.  Just make sure you do so in a covered area so they feel a bit more comfortable (and can't be swooped down on!).

One note about the cow's milk, however, it is best to give milks with no lactose in them (such as puppy or kitten milk replacement), as cow's milk usually gives baby mice diarrhea and can hurt their tummies.  They are very lactose intolerant!  Other than that it sounds like you're doing a terrific job, thanks for watching out for these little guys!

-Tam