Shawn,
There are two main killers of HSBs in my opinion. One is predator fish when stocking small HSBs, and the other is fungal infections from handling in cool weather. Just do some walking around your pond and look closely for fish that have cotton-like growth on their tails. If you don't see any of that within a week of stocking then I'd say you are in the clear as long as you don't have large predators.
Your HSBs should feed through most of the winter in your area.
Nobody can say what your survival rate is, and only you can make a guess.
