Why is my 3-week-old kitten not active and playful? Is it sick?

Usually kittens are rather playful at this age, but occasionally some are not very playful.

It's good to check that she's not unhealthy though, because this can cause a decrease in activity.

Check her gums - see if they are pink or white. If they are white, then he may have anemia.

Check the belly - see if it's tucked in or is it round and distended. If it's round and distended, then he may have worms or other intestinal diseases. Most kittens get worms from their mothers, so if he has never had deworming medication, then it would be good to do this.

Make sure he is eating and drinking well. Also make sure he doesn't have diarrhea or vomiting. These things can indicate that there is a disease causing him to be less active.

The best thing you can do is have a veterinarian take a look at him. They will be able to tell if there is something wrong with him.

I hope this helps.