It should state on the pedigree though if they have an ear number. All of my pedigrees have it I the top left corner. Also, most of the pedigrees I have that have a rabbit listed as a number have had recent additions by the breeder I then bought the animal from. They simply put the name they chose for the rabbit in parenthesis behind the number. Some poor things have several names, just crossed out one after another.
I would go ahead and put the rabbitry name and hen whichever name you choose. The only thing you don't want to do is change the ear number up if that's already on there. Even if the pedigree has it written in and the animal doesn't. My two newest angora does have a number on their pedigree, but its not tattooed. This, when I break out the tattoo gun next time I have to put their assigned number in their ear, versus what I would usually put in heir ear. ( I use names of the breeders since I don't show and that helps hubby find out who's who when I go out of town, and kits get 'PSF' for postage stamp farm folowed by their parent initials and what number kit they are from that particular pair.
For example, my rabbitry is the Heathertoft Rabbitry. One of my new home-bred kits is Poker Face. Her name on her pedigree will be Heathertoft's Poker Face. 
