Kittens often purr when they are happy, content, or feeling relaxed. If your kitten is purring while being petted, held, or while lying down, it's a good sign that they are feeling happy. A happy kitten will have a relaxed body and will not be tense or on guard. They may be lying down or sitting comfortably, with their tail relaxed. A happy kitten is usually full of energy and loves to play. They may run around, chase toys, or engage in other playful behavior. A happy kitten is usually friendly and enjoys interacting with people and other pets. They may approach you, rub against your leg, or sit in your lap. A happy kitten will have a healthy appetite and will eat and drink regularly. They should also be using the litter box consistently. A happy kitten may meow or chirp in a friendly and content way, especially when being petted or held.