[YorkieRose]

Xrays, when read by a professional tell you how many pups..and not a whole lot more. Puppies come heads or tails, either position is safe...it can take a bit more time for a feet first puppy...especially, with a first time whelping.

I have had just as much trouble getting a big head out and as tiny feet first...
Like the head of a human baby, the pups head is soft and maliable..I have seen huge heads in an xray pass easily through a opening smaller..measuring the size of the head and the pelvic opening is not a given..big head pass..big head get stuck..same with small heads..

If the pup comes feet first, you need to give it a few swings downward to clear any fluid..but I have needed to do that with head first also...

If you have the good fortune of having pups all about the same size, you should be ok...trouble can come when there is a big one and it is first...but even then I have seen them pass with no trouble and the mouse behind it refused to budge...it is a pure crap shoot.

I have seen bitches whelp one large pup and have a section with a tiny one...breeders are gamblers...best wishes...