Hi, Sorry to go over this issue again, I have read some older posts but I am still confused about pig ID. On my sheep they all have an individual number/ear tags, the two GOS gilts just have a number 16 & 19 tattooed in the ear. Can I just add my herd number to them prior to slaughter with a slap marker or do they also have to have individualally numbered ear tags as well? Cost of slapper kit & tags adds to the costs. Ron