Why not let the wolves at ‘em?
Back in the early days they used mercury in tanning which almost entirely stops decompostion.
First problem is that log houses if well caulked are naturally well insulated. This means the cows will thaw slowly. The ones nearer the outside will thaw first and the ones in the middle will stay frozen longer.
Rotting large animals will liquefy internally and bloat with gas until their skin ruptures spilling the liquefied internal organs. With the large animals and large amount of liquid the concern is that this bacterial soup will contaminate the spring water that locals drink from.
The reason you can not leave the cows to the wolves is that wolves are highly territorial and this amount of bovine flesh could not be consumed by the local pack by it self before the contamination of the spring water.