[Cazador]

Ytee,
You want the meat to be at room temperature for sure. Don't serve cold meat to an ectotherm. I cut it into the right sized strips, according to the size of the snake, and freeze them separately on freezer paper. After they've frozen, I thaw as many as I want in hot water. Then, they can be scented if desired, added to shallow water with live fish, or they can eventually be presented by themselves in a dish. Sometimes, I even thread them onto light fishing string (with a needle) and give them a little motion through the tank. I tie a small knot in the end of the fishing string, so there is a tiny bit of "struggle" when it gets "captured." It's a lot of fun, but it takes them a bit of time to get accustomed to it. I'd suggest starting with the meat in a shallow dish with live fish.

Abcat,
I don't know why the heart wouldn't work as food. It has a bit of a different texture and flavor, but it should work. Just wash and rinse it well, and try serving it beside your pinkies. Be sure to occasionally supplement the meat with Calcium powder & vitamin B1. There's nothing to lose in trying, right?
Rick