How much milk should a 3 week old pup be drinking?

every pup is different and nobody really knows the answer to this question but a good indication that it's getting enough milk is that it's either too fat at which point you have to cut back on it's milk or it's just right but you have to be careful if you have a shy runt in your litter try and make sure that he/she is getting enough milk as well because they are tend to get less and make sure the bigger bossy leader of the litter type pup doesn't get too fat cause that can be very serious too