Personally i wouldnt take a kit under 8 weeks old regardless of how much the breeder sayes there ready,they should all be eating independently ,they should be tazzing round the run , sadly it looks as though these ferrets are in a fish tank but thats another thread
They should be bright, alert, hand friendly, pretty much bomb proof if the breeders taken the time to do the job properly, personally i wouldnt take a ferret who didnt look right, make sure theres no sniffles, sneezing going on & have nice clean clear eyes.
Lastly they should be plump , not skinny & have nothing ot