My Mouse Diary-Catch and Release

I am holding a field mouse captive in my house. This is a fact that bothers me. He's in a "Have a Heart" cage and it's roomy enough for him, so I'm not hurting him in any way, I feel. He (or she) crawled in there of his/her its own volition. I did not chase it down, throw a net over it and wrestle it to the ground or anything...the problem ? This is Vermont and this is Winter in Vermont.

Day One--yesterday AM-- it was hovering right at 0 degrees F with a wind  chill factor of the NORTH POLE when I noticed that the trap had been sprung. I couldn't get myself to toss it out into that weather (or 3 miles down the road, as is my typical modus operendi) so I gave it some sun flower seeds and went to work.

Day One PM- I got home and it was even colder! Again, I couldn't do it. So I found a small plastic container, filled it with water and put it in the cage along with "dinner"--meaning more small black sun flower seeds and one big almond. At night, I put a towel over the poor guy's cage so he wouldn't be cold.

Day TWO- AM-- Minus 8 degrees below zero when I woke up and checked on him through the bars of the cage. He appeared dead, but the poor guy was only sleeping. I checked his water, noted that he had eaten many of the seeds and had slid the seed pods out of the cage  (hey, he's tidying up, I thought). I put more seeds in the cage and a little dried up omelet section (I figured he needed some protein) and covered him back up for the day. He seemed pleased.

Day Two --PM--Still cold. Couldn't do it.Gave him more water and food. Covered him up for the night.

Day Three--AM Checked on Mr. Mouse. Told him tonight I was going to let him go "at a barn"

Day Three--PM--Went home. Turned up the heat. Took the little bugger outside, put him in my warm car and drove him 2 or so miles away up to a horse barn with tons of hay and two very nice horses. There was a "spot light" there for the horses to see, apparently, so Mr. Mouse could see what was what when I opened the cage. He looked SSOOOOO tiny text to the horses and barn, out in the open like that. So tiny and helpless. And he looked over his shoulder at me on his way to the barn as if to say, "You? Can go to H E Double Hockey Sticks!"