Kittens can normally begin to improve themselves from off their mother's milk and begin eating solid food at around 4-5 weeks of age. They can normally be completely independent and separate from their mother by the time they are 8 to 12 weeks old. Taking kittens away from their mother prior to 8 weeks of age can lead to lasting health and behavioral repercussions. Although 8 weeks is the advised age for weaning, it is essential to remember that this must be done carefully.