Goldfish pond or tank for the winter?

My husband does some volunteer work at a buddhist temple. The monks created a small pond this summer, about the size of 3 standard bath tubs. There were 17 goldfish in it, not sure what species. Not sure how well they were fed. They took all the fish out and put them in a 20 gal tank for the winter, about a week ago. Way over crowded, no plants, etc. My husband said the water is gettting gross. I don't know if they have the room to add more tanks to split the fish up.

Fish can survive winter in a pond, as long as you keep the ice broken at the top. Apparently, they hibernate if they were fed well in the summer. I am in MD, we get plenty of ice but it is always thin, so it would be easy to deal with.

My question is, should I just have the monks dump the fish back into the pond and give them some instruction on care? Or will this shock the fish? The temps here are fluctuating like crazy but it will be steady in the 40s for a few days. May be able to talk them into a second tank to split the fish up.

Any thoughts here? I am going over tonight to at least do a water change, worried about these poor fish. Thanks!!