
As somebody who lived for a while in Canada, importing into Canada from the UK when needed, I can say that the breeder (British) of my foundation bitch HATED exporting her puppies/youngsters and usually only did if she knew the people (as was the case with me). I wanted a good bitch intending to mate her to my second UK bred hound and knowing that, she had the breeder of my second hound 'help' her decide which would be the best of two she had available, to send to me. That's the ONLY way I'd have got her to send me anything. And it was done by phone, NOT by email!! She much preferred all her buyers, domestic or elsewhere, to visit and choose the pup they wanted! Quite sensible if you think about it as it avoided 'disappointment' when opening the travel crate!! As was the case for me with another pup (7 months when he arrived in Canada) who I'd bought from another UK breeder I'd known for years, having been sent photos. He wasn't really as good as I'd hoped BUT he was really bought for his bloodlines, much as he did gain his Can.Ch. and ended up back of all our subsequent litters, both Canadian-bred and back in the UK.
Many breeders will export to the US, but equally, many won't. However not to answer an email is bad manners in my eyes, but perhaps your email didn't arrive, or perhaps as she has nothing available, she's simpy not bothered to tell you so. If you really want her specific lines, why not phone!!
ps It is the holiday season right now, and even if she's not away, if she boards, she may be ultra busy and equally not have anything available. A quick email to that effect would be polite tho.!