I'm sure there probably are some people. None of the folks I know who breed and show kill puppies who don't meet the breed standard. Some are kept because they show promise (and occasionally rehomed as older puppies if they don't) and many are sold as pets with a spay/neuter contract.

The only "breeders" I know of who have (or tried to) kill puppies due to deafness have been people who shouldn't have been breeding in the first place (e.g. the guy who bred a merle Aussie to another merle, sold the hearing puppies at 6 weeks old in a Walmart parking lot and then was going to take the two deaf ones to the vet to be put down; luckily an Aussie rescue person just happened to be there at the store that day and as able to save them).

Of course, plenty of those types of breeders sell deaf puppies either without knowing or without letting the buyers know.

Sadly there will always be the wrong type of person breeding animals to make money

Some of you, I am sure will know of me

I for one am against disabled pups being pts (unless they are suffering physically or mentally)
I had never considered myself as capable of being owned by one but having taken the plunge I now think they are amazing BUT I still wish there was a way to stop them from being born in the first place.

Teija was my first lethal white BC.
She was born deaf and blind and through establishing a way of communicating with touch she not only learnt basic obiedence (sit, stay, come etc.) but also did agility for fun, even the jumps! Sadly we lost her after 5 short years to a massive fit in January 2011.

I now have 3 Border Collies.
KALI was born with eye trouble and after several ops she still has visual problems but is very happy and content with life and you'd never guess she has problems.
BEREZI was born deaf, blind in one eye and with tunnel vision in the other - we communicate by sign language and she has her Bronze KC Good Citizen Award (we are woking towards silver) I work with adults who have learning and communication difficulties and they love it that they can sign to Berezi and she will respond.
KASHI was born deaf and blind - he is the baby of the bunch and is learning touch signs.
He is from the same mum and dad as Teija and however morally wrong it may seem to breed them again and again knowing some pups may have disabilities no laws are being broken.

Please look at my website to read more about Teija and lethal whites.