Why is my mama cat still nursing her 8 wk old kittens

Some people put them (the mama and the babies) in opposite ends of the house, which can sometimes work. But if the kittens know their mama is close by, they won't have much incentive to eat on their own. As long as they are acting fine and still interested in nursing (i.e. they have an appetite), it won't hurt them at all to stay away from her. They'll eat when they get hungry enough. (You might have to help them discover it by putting it in their mouths with your finger.) Just make sure they are getting plenty of water. (I'm assuming, of course, that they were appropriately dewormed and found to be coccidia-free by your veterinarian.)

Here's the biggest thing, though: I sure hope you've been keeping Zoe indoors ever since those kittens were born. If she has been outside at all, there's a good chance she's already pregnant again, even though she's still 'nursing.' Cats commonly come into heat again when their litter is only a few weeks old..they are what we call 'seasonally polyestrous.' (Dogs are different in that they generally won't come into heat again so soon.) That's the biggest problem we have with getting cats spayed during the spring/summer months (year-round in southern climates.) By the time the milk has dried up enough from the first litter for us to do surgery, they're too far along with the next pregnancy to do it. And thus the cycle continues..and you're facing the same thing all over again when it's time to wean the next litter. That's why they need to stay indoors after giving birth, until we can spay them. (None of us like to spay pregnant cats, if it can be avoided..and if it just HAS to be done, should be done within the first 3 weeks of the gestation.)