How to choose an healthy kitten?

The first way is to buy a kitten from a responsible breeder. But how can you find a good breeder?
When you first contact a breeder you chould expect the breeder to question you about your family, your other animals and the reason for why you have decided you want a Devon Rex.
Be wary if the kitten price is too low.
Ask to visit the breeder's home to see the kitten in his enviroment and see how the kitten is raised.
Ask to see the parents of the kitten (it's possible the sire is not at the breeder home) and the other cats.
Look at how the cats are kept: are they clean and in a good health? Is the home or cattery clean? Do they have clean water and a few cat toys to enjoy? Are the kittens frightened by you or do they seem to be playful and outgoing?
Listen to your istinct and you will make the right choice !
If you don't think a breeder keeps their cats in the right way simply don't buy and contact another breeder.