Our Duroc crosses always POPPED at about 50 pounds,going from 50 to 100 in what seemed like a week. Our Duroc sow was one of the sweetest, most docile pigs we had. She punctured a back leg on something in a wallow at about 700 pounds and got an infection in the bone that we couldn't clear up. She wasn't able to bear weight on that leg and was essentially immobile so we had to euthanize her, it was a sad day as our breeders are more like pets.
Try getting your fat to almost frozen and running it through the meat grinder before rendering it. I found this to allow it to render faster and more completely but, you don't get the larger cracklins this way. I would load my fat into a cast iron Dutch oven and put it into the oven at 215F, this was just hot enough to boil out any water but not hit enough to burn the lard. I'd ladle the lard out hourly and add more fat. I liked to filter my lard through 5 or 6 layers of cheese cloth, my leaf lard would come out pure white and odorless.
