Newborn kittens are indeed a lot of hard work, but mostly for the mother cat -- the queen. Until weaning begins, your job as a caretaker is to ensure that the mother cat receives proper nutrition so that she, in turn, can properly and adequately nourish her wee fluffy bundles.
Nursing Kittens
By nursing her youngsters, a mother cat totally manages all of the specific dietary necessities of her litter. From the initial antibody-packed colostrum to the appropriate amounts of vital fats, proteins and vitamins, the mother cat's milk has everything the little ones' bodies need to grow healthily. Because of that, newborn kittens do not need food until they're old enough to begin weaning.
Weaning
When a wise mother cat determines that her kittens are mature enough to begin eating solids, she'll slowly but surely start deterring them away from nursing as frequently as before, though she will continue some of it. Kittens are usually old enough to start eating solid foods when they're around 3 or 4 weeks in age, according to veterinarian J. Veronika Kiklevich of CatChannel.com. They're usually read to eat solid foods exclusively when they're between 6 and 7 weeks old. By then there is no need for them to nurse with mom.
Solid Food for Kittens
When you begin feeding kittens, offer them small portions of commercial foods that are made exclusively for their young age. If the label doesn't say "kitten," it isn't appropriate for their tiny growing bodies, so don't feed it to them. Always make sure that the food is wet and chewy. Soft food is much easier for kittens to manage -- remember, they've never eaten solid food before. Whether the food is canned or dry, blend it thoroughly with kitten formula that is slightly warmed. Once they're around 6 weeks old, however, you can stop mixing the food in with formula.
Absence of Mother
If you for any reason are caring for a motherless litter of newborn kittens, then feeding duties are up to you starting the first day -- unless, of course, you have access to another lactating queen who can serve as a substitute. This is also the case in the event of an ill mother cat who simply is unable to properly nurse her kittens. If this is your situation, then you need to invest in both a kitten milk replacer and formula made for kittens -- both of which are readily accessible at the majority of pet stores. Though you won't have to give the little ones "food," per se, it's up to you to personally bottle-feed them via the milk replacer. If you have any questions at all about newborn kitten feeding, consult your veterinarian pronto. Also remember that cow's milk is no replacement for a mother cat's milk or kitten formula. Not only does it fail to satisfy newborns' dietary demands, it can give the poor things digestive upset.
Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.