half a cube of ferret gruel

I found that the ferrets will lap up half an (ice) cube worth of gruel with a couple tablespoons of water. I defrost the half-cube for 25 seconds in the microwave, squish it with a fork, and then blend in cold water with the fork. I've been cutting the cubes in half with a sharp knife and saving the other half for later in the freezer. That way, I don't have to throw half of it away, since they don't seem to like it after it has sat in the fridge all day.