Mika got her first jab with the breeder at 6 weeks old then her second with me at 8 weeks old she was already 2lb by then but must have been less when she had her first. Also when I used to keep ferrets I used to have them vaccinated as babies and they were much less than 2lbs (my tiniest one was only 1lb full grown) and they were vaccinated with the EXACT same jabs that they use on dogs (smaller doses obviously). Some adult yorkies are only 3lbs or even alot less full grown, does he not vaccinate these ones til they're 2lb too? What if they don't reach that til they're a year old or more?
Maybe the vet doesn't want to give these particular pups their jab yet for some other reason
I don't know
Or maybe the breeder just loves her babies sooo much, she wants to hold onto them that little bit longer to give them more time with their mother and she just wants to give their new families some more reasons for holding onto them
Don't worry she will be home with you soon enough