Do all kittens need to be bottle-fed? - Oakdale Veterinary Group
The small ones need to bottle-feed if their mom isn’t able to nurse them. If they can't eat solid food, then they need to get their nutrition from milk. If they are already eating solid food, there's no reason that they would need to have milk. By about nine weeks, kittens generally don't need milk.
Do all kittens need to be bottle-fed? - Advanced Animal Care
No, it's an age-dependent necessity. Those younger kittens that are purely on milk at that stage in their life need to be bottle-fed. But as they get a little bit older, again that six-week mark, we can go ahead and transition them over to dry or canned kitten food.