Matjen,
Not quite sure I fully understood your original post.
I presume that the boar moved onto your holding with all the relevant paperwork (either the old paper one, or on e-aml2), and has a tag which has the herd no. of the owners.
So when you say they want your holding no. I presume they want your e-aml2 login, as they’ll already know your holding no. from the paperwork when he came. As others have said DO NOT give out your username.
If he did come without a movement form, so is technically not on your premises then come back as the “answer” will be different.
I also presume you are in England & Wales (E&W) - if you’re in Scotland the principals are the same but the process is different.
Legally, the move is from your holding to market, and under e-aml2 you’re the only one that can enter the details, as the system only lets the holding do a move.
Ownership has nothing to do with animal moves, the law states that the “keeper” is the one responsible for doing the move, and defines keeper as “means any person having care and control of pigs, whether on a temporary or permanent basis, but does not include a person who only transports pigs”
If he came with paperwork, this is no problem, just do the move for you to the market, and in the “lot numbers” bit put his herd. No. (and individual ID if he has one). Tell them that as keeper this is your job – they may simply not understand this.
Print 2 or 3 copies – one for the the owners, one for the transporter if different, and one for the market – whilst the system is s’posed to be electronic so they don't need it, many markets like a bit of paper as this shows that you have done the on-line bit.
If the owners still insist on doing the the paperwork, then giving them your holding no. is no problem – after all they already have this. DO NOT give you e-aml2 login – if they really think they should do it, then they can phone the e-aml2 helpline and see if they’ll do it on the phone – suspect they won’t unless they are lazy and don’t ask if you the person who has the holding, but hwo know with MLSCS. If they do, you’ll see it come up on-line for you, but get a copy of the paperwork to be sure. If it isn’t on your system, then don’t let the move happen, you will be the one whose records will be wrong.