[Hassle]

I just read that OSB have to be notched and or tagged, what rules apply, if any,  to GOS (not going to tag until their going to slaughter though)

GOS if you are keeping for breeding and showing require a tag and tattoo, however if being kept for meat the only a slap mark is required. Slappers are quiet expensive so find some one local who can hire lend and then just buy the letters. Don't forget to wash and sterilise before you return