Joanna, I disturb mine when I'm checking their food level or adding more. They don't seem to mind. I move the feeding location every time I feed and it only takes a day or 2 for them to find it. I don't know about "all balled up in the center" unless maybe that's the warmer spot, or when the food starts to get depleted they're searching around for more. I think they tend to get lethargic much below 60 degrees. I have an indoor/outdoor thermometer probe in the bedding and it runs around 62 to 69 depending on whether we're running the furnace or heating with the wood stove. The bottom of the bin is maybe 18" off the floor and naturally the floor is the coldest place in the basement. Maybe try feeding them a little more often. Most of what I give mine is green waste, banana peels, coffee grounds, and crushed egg shells. I dice everything up fairly small, 1/4" or so.
