Should I leave the frogs in the frozen pond?
Frogs breathe not only through their lungs but also through the roofs of their mouths and through their skin (oxygen is absorbed in these two areas). Try to keep an air hole by standing a saucepan of hot water in one area each day. I have a piece of the large bubble wrap stretched across most, but not all, of my small, fairly shallow pond and a couple of plastic ducks floating on the water which helps to absorb the effects of the expansion of the ice. I would leave them – only the females prefer to hibernate wrapped up away from water – the males usually bury themselves in the mud at the bottom of the pond.
