Yep .
Really pronounced though ,clearly out from the top lip with no jowl coverage,..

my Missy has quite an undershot jaw, it doesn't bother her, but her teeth do suffer a bit. She gets quite a build up of tarter, and because of the way her jaw is chewing hard foods doesn't help.

Well to answer your original question no I would never KNOWINGLy breed from or buy a puppy with an under or overshot jaw in my breeds which are required to have scissor bite.

In my breed I would never breed from a dog with an overshot jaw. As for buying a puppy it would depend on the age. I have seen several puppies where the upper & lower jaw don't grow at the same time or same rate but in at least 99% of them if the mouth was right at 6 & 8 weeks it will be right at the end.

Definitely not breed from, bad fault. Sometimes you dont know until the dogs older how pronounced it will be. It wouldnt put me off owning a pup/dog that is over or undershot.

I remember a vet telling a young friend of mine, her Boxer puppy woudl need surgery on his jaw ..... because it was undershot

I would never breed from a dog with an under shot or over shot jaw.

If a puppy was under shot then no I would not buy it I would buy a puppy with a level bite because that would likely go under shot.

The top jaw finishes growing first so if the bottom jaw is either level or under shot it will only get worse. I have never seen an under shot jaw correct its self.

An over shot jaw can correct its self if it is not too bad to start.

My Yorkie has an overbite (although it isn't massively noticable). No I would never breed from her. I wouldn't breed from her anyway, but definately wouldn't hypothetically because of the bite fault.

Keira has an overshot jaw, it is quite bad so I don't think it will correct but it might get a little better. I have always had an interest in breeding and would have considered it in the future when Keira was old enough once I'd had her hip and elbow scores done and seen her temperament when she'd matured however with the overshot jaw it has taken that decision away from me, she will be spayed after her first season

Its dissappointing if you really wanted to breed but IMO there are enough 'faults' within each breed without adding any that we know of previously, having said that I am in no way an expert or a breeder its just my opinion

I would not do anything just yet. I would wait until she is at least 18 months if everything else is good.