In posters experience at what age are pups considered viable to be born.I know in theory it is day 57 onwards but what do those who breed think of this.

Four pups born day 54.
I lost 2 and reared 2 at 2oz...... One became a UK Champion.

In Cavaliers day 57 is very common.

My Chihuahua Long Coats mostly go to day 56.  Pups definitely viable.  Even though they are so tiny.

So I have always said that 7 days early is normal for my breed. 

I had one bitch have a large litter 10 days early.  I would always say to people that they won't survive, and you're wasting you're time trying at this stage.  Yes,,, easy to say.  Not so easy to do though.  I tried so very, very hard and it broke my heart.  The bitch pined and pined, it was awful.  But the lungs just aren't developed enough at this stage.

I so much prefer what I call a "normal" litter 1-3 pups.  That is plenty for a bitch this size.  My top bitch only ever had 2, just right. 

Had a litter of 13 born day 57 medium gundog breed, all were fine.
Diane

Had a litter of 7 toy breed day 56, all fine. First time mum and she was great, quite a surprise though...