[member=178474]ann_of_loxley[/member] , Close, but no cigar!
They must be wearing ear tags when they transfer into your ownership (and from your original post, I kinda thought they were already?).You don't have to do anything with those tags - they keep them for life.
For now, let's just assume they'll come onto your holding wearing double (breeding) tags. If they come on with a single (slaughter) tag then that's slightly different, so ask again if that happens (no point in complicating things now!).
What I was trying to say above is that if you don't like the type of tags they come with (say they're too large for your liking, and you're worried they'll get caught on things), then you may if you wish replace them with another type, like the bubblegum tags. However, if you do that, they'll be 'replica' tags, and will carry exactly the same information as the originals.
For info, both tags carry the same information, i.e. flock number and individual animal number. The only difference is that the yellow one has an EID chip in it, whilst the other one (colours vary) only contains the printed information.
Does that make sense?