What is the appropiate age for kittens to be separated from their mother?

Eight weeks at minimum. Twelve is better for them. If they’re still nursing, you see
that as a signal, right?
One reason they need to be with their mom is that they can’t defecate without help till
they get older. That’s why their mom licks their bottoms – not to clean them AFTER they poop, but to get them pooping.
You don’t want that job. Or the job of bottle-feeding.
Let nature do its job.

Ok. Thanks!!!! I“ll wait….

well minimum would be 4 weeks you can start feeding them soft food at 4 weeks just get dry kitten food and add water then when its all soaked in let them start eating it but average age is 6 weeks

The mother of our older cat gave up on the litter at 4 weeks. When we brought him home and tried to bottle feed him, we found out why. His teeth were quite developed and he ate two nipples from the bottle. He managed just fine, but I agree that waiting until eight weeks is typically better.

Her previous litter nuesed till 6 months!!! The pooping thing is very true. Maybe I should start feeding soft food? They’d become more independent and poop by themself?

At 4–6 weeks of age, you can introduce soft food. Initially, the kittens will spend most of their time walking through it and tracking it all over your kitchen. Keep exposing the kittens to the novel food source and they will gradually get better at eating on their own. During this process, they will continue to nurse. Usually by about 8 weeks, they are completely comfortable eating solid food and you can begin the transition for dry food. When kittens are able to easily eat dry food, they are ready to be weaned and can go to a new home.

Contrary to popular myth, the queen can indeed get pregnant again while nursing her kittens. Keep her inside until the kittens are weaned, give her a day or two for her milk to dry up, and then take her in for an ovariohysterectomy (spay).

This morning I witness the kittens actually eating normal grown-up cat food. I remove them from the plate worrying that it could be perjudical to them. I’ll prepare soft food when I get home. I suspect that when they start eating soft-dry food they will start pooping by themself, am I right?

They should already be pooping by themselves. If you make a litter box available (with low sides so they can get in and out) I think you’ll find that they do everything on their own now.

If they are capable of eating dry food, it’s fine to go ahead and try them with dry kitten food. It’s just usually physically easier for them to start with soft stuff.