Quote:
Originally Posted by Susan123  You don't want them to keep going for too long. If she conceived on the first tie and then on the last (say 2 weeks later) The first puppy will be premature. They drop multiple eggs during ovulation. |
Taken from "The Dog Breeder's Guide to Successful Breeding and Health Management" by theriogenologist Dr. Root Kustritz...
When asked about a runt puppy being conceived later...
"Dogs release all their eggs over about a 24 hour span. Even if conception of that small pup occurred later than conception of the other pups, all the pups float around free for 17 days before implantation and formation of the placenta. Runt pups most likely are the same age as littermates but had poor placentation."