That's from rendering (slow low heat) the raw fat from older hens?
I've used the fat from older hens, as well as fat and skin from CXs. The older hens are more flavorful.
I do a fast rendering process. I cut up the chunks of fat and skin and put them in a pot with about 1/2 cup of water. I then cook it for 15 or 20 minutes on med-high until the fat melts and turns golden and the bits of skin get crispy. Then cool it a couple of minutes and strain it. It's really easy to do, and keeps for several weeks in the refrigerator.