I don't have any direct experience on catching cats in the winter, but I think you're on the right track with chumming the area you're going to fish at.

You could also try scenting the bluegill chunks with some attractant.

Excerpt from Robert Crais' "The Monkey's Raincoat:"
"She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."