Firstly, nothing you do now will change the numbers in the sheep's ears. Sheep are tagged shortly after birth, with the flock number of the flock into which they were born, and that number never changes.
Similarly, those ear tag numbers are now registered as being on your grandpa's CPH, and you can't change that unless you either physically move them to another CPH, or create a second CPH for yourselves on his holding (which would require his agreement, natch.)
Afaik, no-one keeps track of who owns sheep. The keeper is the person responsible for their welfare, and is only recorded at the time of a movement, and may or may not be the owner of the sheep, may or may not be the person associated with the CPH : no-one cares. You can record one keeper as you move them on and a different keeper as you move them off, and no-one will bat an eye. Transfer of ownership if the sheep stay on the same holding is of no interest to the government.
The owner of pedigree sheep is of interest to the Breed Society, so if you want to be recorded as the owner on the pedigree papers, you can do that.
Next wrinkle is new (as yet unborn) lambs. If you don't set up a separate flock number, then by law, all lambs born on the holding will need to be tagged with the current flock number, ie., your grandpa's. Afaik, it is perfectly possible to have a second flock number for the same holding, so you should just need to explain to Animal Health what you are doing and they should be able to assign a new flock number for you. You would then tag lambs born to your ewes with your flock number.
Similarly, the Breed Society should be happy to assign you a Breed flock identifier (however that is handled for the breed in question, they seem to be all different!), so talk to them about that.
I am not 100% sure how it would work in terms of annual return / inventory and so on. There is one that is for all livestock on the holding, so presumably your grandpa would just include your headcounts in his return for the CPH. There is another specific to sheep and goats, and that might be per flock number, so you might each get one of those (and you would need to be sure grandpa understood to not list your sheep on that one... :exploding_head:)
If you can achieve what you want just by having your details with the Breed Society, and your own Pedigree Flock Identifier, I would think that would be considerably simpler and easier to manage than having a second CPH or flock number and all the government red tape that goes with those.
Topic: CPH and Flock numbers (Read 1836 times)
