How old do kittens have to be to safely take away from mommy cat?

They need to be 8 weeks. Its better to measure it in weeks because at this young age a full month can mean a really big difference. They should usually be weaned from mom at 6 weeks and need to stay with the family until about 2 weeks after that, or 8 weeks.

at least 6 weeks. or if they are able to eat cat food on their own. you might need to soften the cat food at first. mix it with water. If the kitten won't eat it, try feeding it off your finger. then see. if they accomplish this they are ready. Some kittens can't keep down kitten food. So I suggest trying that first then if it doesn't work you can take regular cat food, and a can of moist cat food, mix the dry cat food with water then add a little of the moist food's juice and see if it will eat that. if there is still nothing then it's probably not ready yet.

6 weeks

Minimum of 6 weeks I recommend 8 weeks.

From six to eight weeks. ( eight weeks is better ) The mother cat will usually let you know when the kittens are weened because she won't fuss over them as much and spend more time alone.

until they are fully weaned. so to be sure, i would recommend a minimum of 8 weeks, preferably 12 weeks. by 12 weeks the kittens will finish learning from their mom.

As soon as the kittens are born they must immediately be sacrificed to ultralord and the bones must be eaten by the mother

at the very least 6 weeks.