Ground beef already formed into patties or separated into smaller quantities take less time and defrost quicker. For instance, 1/2-inch (1.25-cm) ground beef patties that were frozen separately usually take about 10 hours to defrost.
Gelatin is a protein substance used to thicken liquids. It does not have a color, smell, or taste. It comes from boiling animal tissues such as beef bones, cartilage, tendons, and pig skin. Gelatin is used in many kinds of food products and drug and supplement products.
Most commercial gelatin in  the US is a byproduct of pork processing and does indeed come from  pork. Gelatin derived from other animals is available, though not  as widely as that from pork. For example, fish gelatin is used by  one Kosher candy company to produce marshmallows.