I have no idea so this isnt an opinion just an experience, Ive just bought (2weeks ago) bought a kitten, he was 9weeks when i had him fully weaned and litter trained and absolutely fantastic. I was given a tin of lactol to feed him on and when i went the vets last Thursday to get his first injection the vet asked me if he was eating/drinking ok.... to which i replied "like a pig" lol and explained i give him lactol still and she told me to take him off it if hes fully weaned but he can have it if he likes it (he still gets a bowl a day cause he loves it) Hes settled in really well and has had no problems hes a pleasure to have around, when hes not breaking my vases

Good thread, Informative and everyone has their own opinions I think its personal preference as some breeders like to know their kittens go fully vaccinated, some think the new homes should make their decision, and others like to know the kitten is of an age/temperament suitable to go to a new home.