Kittens start from birth, that is to say, kittens can try to wean in about 40 days at the earliest, and in about 60 days at the latest, depending on the mother cat's milk.
Often some female cats don't have much breast milk from the beginning, and may naturally return to milk after 40 days. At this time, it is necessary for the owner to supplement some milk cake food to the kitten during weaning.