I feel that too often these days, the practicalities of birth and rearing young are unknown territory for 98% of the population.
Some people will remember their cats having kittens when they were young - was there any problem? No - mother cat would have her kittens somewhere nice and quiet, and she would deal with them, cleaning them up, looking after them etc and, after 6 weeks or so, homes would be easily found for the resulting kittens - who would, of course, being feline rather than canine generally use a litter tray - or at least would poo and pee in a corner ;) !
Whilst a bitch will "usually" have an easy birth, the comparison stops there. Puppies are by their nature, noisy - they squeak and squeal far more than most kittens, and whilst kittens, once on their feet are quite nimble little things, puppies can seem far more clumsy. Whilst mum will clean them up whilst they are solely dependent upon her for food, once they start taking in solids, bitches are not so keen ...:rolleyes: - and puppies unlike kittens do not seem to be aware when they are evacuating their bowels - they poo, they walk backwards through it, they climb over their littermates, they may even poo
on their littermates

In short, there is a lot more poo to clear away with puppies ....think about it ....a average-sized litter of 7 puppies will each poo after each feed - 4-5 feeds a day at first - so that means that the breeder has to clear up 28-35 poos per day! And that will also mean that 7 puppies will each need cleaning up 4-5 times a day :) - that's an awful lot of clearing up!
And that is just the most basic of care - to raise a litter entails far, far more care than this.
Margot