Kittens can’t have a bowel movement on their own until they're 2 or 3 weeks old. Until then, the mother stimulates elimination by licking around the kittens' anal areas after feeding. If you’re hand-raising a kitten, you’ll take on this task until the kitten has the physical capability to eliminate without assistance.
How to Stimulate Elimination
A healthy mother cat grooms her kittens after every feeding, concentrating on the anal and genital areas. This naturally stimulates them to eliminate. You can simulate the mother’s actions by rubbing a wash cloth moistened with warm water around the kitten’s anus. You can also use a piece of gauze or a cotton bowl, both of which are similar to the texture of the mother cat’s tongue.
How Often to Stimulate
Kittens need to eat and eliminate frequently; the younger they are, the more often they should do both. Kittens less than a week old typically need to eat and eliminate every three hours. Between 3 and 4 weeks of age they may need to eat four to six times a day. Feeding frequency decreases to four times a day at 6 weeks and three times a day at 12 weeks. By this time, kittens might not have a bowel movement after every feeding the way they did when they were younger, but they should eliminate at least once a day. If an older kitten doesn’t eliminate after a feeding, you can try again after the next, or after she’s played or had a nap.