"How Old is that Kitten?"
Kitten Progression: Three Weeks Old
By the third week, you can clearly determine if the kittens are boys or girls. (Darling, Denby, Corduroy and Tweed are all boys, Wembley is the only girl) Their teeth are coming in and their walking is becoming more confident.
Fifteen Days Old
Even at this age, the kittens still spend a substantial part of their day sleeping.
Sixteen Days Old
The kittens are just beginning to play and develop their fine motor skills.
Twenty Days Old
Kittens this age can start to eliminate waste on their own, without the help of mom or a caregiver. Now that the kittens have reached this milestone, it’s time to start litter box training.
Three Weeks Old
If you are bottle feeding, you'll notice the kittens are drinking much more at each feeding, but at fewer feedings, probably four to five times a day. At this age you can start introducing solid food—use wet food at first, and try mixing it with kitten formula. By the end of the week, their weight will have increased to close to 15 ounces. They are walking steadily, without too much wobbling.