This Except I hit them with a hair dryer before feeding. The hair dryer adds a little heat and gets the sent moving around the room. I usually shoot the rat with a laser temp gun right before I feed, so I know I'm in the right temp range. Too hot is just as bad as too cold.
Where can I get a temp gun??
I thaw mine in a bowl full of the hottest tap water until the water is cold; dump water and add fresh hot tap water (as hot as it will go). Feed. I don't dry mine off, though.