Why is my 4-month-old kitten sleeping all day?

Kittens, like babies, need a lot of sleep for growth and development. At 4 months old, your kitten is likely sleeping a lot to recharge and grow. It's normal behavior for young cats to sleep for up to 16 hours a day. If your kitten is eating, playing, and using the litter box normally, there is likely no cause for concern.