The age of a kitten helps determine the proper way to care for the baby and helps know what to expect from him. Six-week-old kittens are changing and growing quickly. Size for several reasons may not be the best indicator of age.
A 6-week-old kitten has grown quite a bit since he was born. He is now around a pound. His exact weight is dependent on his breed and his individual general health, which may depend on his rank in the feeding line. Kittens with worms, those who come from large litters and those that are orphaned may weigh less than a kitten of the same age who came from a smaller litter or whose mother was healthy and well-fed during the pregnancy and while nursing.
Along with determining how much your kitten weighs, observe how mobile he is. At 5 to 6 weeks old, kittens begin to raise up on shaky legs and take their first tentative steps. Within days, if not sooner, learning to stand will turn into walking and crawling out of bed. Before you know it, the wobbly walk will transform into a full gallop. Prepare for these exciting days by making sure his bed is in a safe place where he has little opportunity to get stuck behind furniture or boxes where you cannot reach him.
At 6 weeks, a kitten is ready for more than just mother's milk. In fact, some kittens may already be chasing mice. Begin introducing food, but do not separate the kitten from mom yet. For a week or two longer, mother will provide milk to help him stay healthy and grow. When mom is ready, she will wean him fully. She may even declare she is not ready for him to eat the food you give him at 6 weeks. She may cover the dish with a blanket to prevent him from eating or hiss as you present it. Continue providing the food, and when she is ready, she will let him eat. In this case, mother may know best -- but consult your vet.
Prior to 5 to 6 weeks of life, the kitten's mother must lick his perineum to stimulate urination, but with mobility comes his ability to relieve himself without help. This is a good time to introduce him to the litter box. Do not be surprised if he sometimes forgets to use the box. He is still a baby and may have a short memory.