I totally agree that kittens and other pets should be sold in good condition and well looked after. Currently under the law it is a criminal offence to keep any animal in a poor condition or cause any unnecessary stress to animals. This includes not treating any diseases, underfeeding or inappropriate housing/environment.
The Government has produced a guide for buying a cat or dog. It gives advice on what to look for when buying a pet to make sure the illegal trade in animals isn’t being fuelled. You can look at it here:
The next time I meet with the Minister responsible, George Eustice, I will raise the point about kittens not being included in the review of legislation.