During the warm months when I'm feeding Optimal I make my own pellet flies. All it takes is a pellet, a small piece of pantyhose material, and a few seconds to wrap the pellet and stick a hook through the pantyhose.
This time of year my pond is usually under ice. It's been on and off this year.
I'll toss a handful of pellets next time I'm out there. That gets their attention when the water's warm. It might work when the water's cold. Only one way to find out.