Do you let people first visit the kittens? And what age do you think is best to choose one?

We used to allow people from 6 weeks once weaning was over but twice had an infection brought in (the second time we lost 2 kittens). We always asked that people don't visit other cat establishments within 2 days of coming to view to minimise the risk of infection on small, unprotected babies. In each case the visitors had been that same day to a very ... overcrowded/not too clean ... breeding establishment and you could smell cats on them. Stupidly we let them in, knowing how far they'd been travelling to look at kittens and thought them to be obviously dedicated in their search for the right kitten. We have never forgiven ourselves for allowing it to happen twice and it still upsets me to think of the little ones we lost. The first was a mild upper respiratory, runny eyes and loosened stools but the second was like a strange plague that saw the kittens deteriorate in days - just going off of food and seeming weak. Injections and pills brough 3 around within 2-3 weeks or so to full recovery but 2 just were not strong enough. I have spoken to breeders where simialar things have happened and so nobody sees our kittens now until they have their first vaccination. When we get any visitors we now close kittens off in the spare room or en-suite and clean the floors when they leave. We had been breeding for about a year when the first case happened and then it was over a year (maybe closer to 18months) that the next did and we stopped all visiting of unvaccinated kittens.

A bit of a catch 22 as we did/do see a difference in how quickly the kittens will "explore" the visitors. When viewing at 6 weeks they were fairly cocky to march up to unknowns and suss them out but now they do need a 5-10 minute sit down before they will trust the visitors and start to explore. By the end of the visit they are fine and usually playing away but it does take that initial time which it didn't seem to before.

There is a fairly new breeder that 3 of our new owners have visited and told us of being shown tiny babies with unopened eyes that are "ready to book" ... I shudder ...

Ah sorry to hear that Yes I have always said no viewings 48hours previous, shoes are left at the front door, (which we anti bac with cat cleaner 99% germ killer before & afterthey place their shoes down) comfy old clothes are worn and we provide anti bac on their hands. I dont know anyone that would let people over as young babies with eyes not open! Thats like a week old?!
I dont even let my family come over (and they have no pets) incase they bring something in when they are babies!!

I also find that the kittens are more able to go up to new owners and bond with them as kittens, then it takes a few mins when they are older, I always say that its like they get to a certain age and realise that Im not actually a cat!!