I picked up some silicone mini bread pans at the thrift store which were perfectly sized for a suet loaf. I scooped out a little grease into each one, about half full, popped them in a 200 degree oven (on a cookie sheet for stability) until they were mostly melted.
Then I filled it almost to the top with some bird seed (for wild birds).
Since it's been below freezing outside, I set the cookie sheet outside to cool down and firm up. Within an hour, it was firm enough to pop out and I wrapped them individually with wax paper.
I'm storing them in the freezer (which you don't have to do if it's cool enough outside, but I actually have room in there right now!) and doling them out to the chickens every week. Each loaf lasts about 4 days.