Hopefully the vet will be able to tell you whether the type of fertilizer used could have been the cause of the hogs’ problem. I wouldn’t have expected a hog to eat it but don’t imagine it would do it much good if it did. But, it’s possible that something completely different caused the problem. For instance, hibernation is a dangerous time for hogs and if they don’t have sufficient of the two fats necessary, they are likely to have problems on emerging.
Sorry to hear about your leg. It must be very frustrating not being able to do things yourself. Let us know if there is any news about the hog.