Yes, as it would throw off the processing time, plus take a lot longer to reach the proper prtessure. Add ice cubes to boiling water and you have no boiling water anymore. Because pork exudes juices it may also be wise to precook it before canning, so its not all shrunken and liquid. I never grind meats if they are partially frozen, as it can stall a meat grinder. A partially frozen meat is easy to cut very thin slices, as it holds up a bit firmer for that purpose.

OK, that's what I suspected. I guess I'll brown the pieces and hot pack them with a stock made from the bones - that would take longer, but likelier be nicer in the long run.

Thank you for taking the time to answer my question.

Exactly what Ken said. You may brown the pieces of pork or beef and add broth to the jars. This way you have the meat in broth and avoid the density issue which you would have if you raw packed. I don't like squishing the meat into the jars with no space in between the pieces. I know the raw pack is an acceptable method however, I prefer the added broth method. If you added salt to the broth, you should add less or none to the jars. Good Luck with your canning.