
They do need more but not much more.
Mine are put on puppy food once pregnancy confirmed, and by the time they are due they are on half as much again as normal, so 300g instead of 200g.
Once pups are born they are fed as much as they like, as that is when they need it.
It is very bad for a bitch, especially in the small breeds to eat too much in pregnancy as a fat bitch is not a good whelping prospect.