
I think I would worry that a breeder might think me too over zealous if I contacted them every week from birth to collecting a puppy. I wouldn't want them to think I was worried about getting the pup or totally obsessed with how it was getting on so would probably contact them a couple of times and then hope that they would let me know how things were going.
It must be quite hard getting the balance right between being an obviously enthusiastic and interested potential puppy purchaser and being wrongly misread as being too enthusiastic and "checking up" on the breeder.