Will my dog be different after giving birth?

Ok, I have a morkie (maltese yorkie mix) and I was thinking of breeding her with a male yorkie because in her state the maltese is more prominent so I think it would even out the puppies, anyway, I'm wondering if my little morkie will be the same after the birthing, I know it will take a little while but after the most puppies are gone (we will keep one or two depending on the size of litter) I have seen so many dogs out there that have massive baggy breasts that almost swing to the floor and are very skiddish or docile or listless after having babies, will my little sweetheart be the same? Or is it only in like homeless dogs? Or big dogs? Or certain breeds? Or breeding too ping or too old? (Pls do not make accusations against breeding I know what the economy is like but I will always make sure i have the room for the puppies before and after they are born and I will have the ppl call me if they wish to get rid of the offspring) thank you for reading and here's to hoping you can answer a question or two :) thanks!