It sometimes happens that 6 cubs are born, also in the wild, usually not all of the cubs make it to adulthood. A few years ago a female cheetah did raise succesfully a litter of 6 in the wild (Masai Mara, Kenya.) The biggest litter cheetahcubs was one of 9 cubs (in South Africa, captivity) of which 7 did survive. They were not raised by the mom but by Zanchieta Wildcat farm.
In Arnhem zoo the mom and her cubs won’t be shown to the public for a while longer as if the mother gets stressed there’s a possibility she can kill or even eat her cubs. So far the cubs are all healthy. Sadly zoos always have a pressmoment which gives a lot of stress to the animals, who already are nervous because of the vaccinations and implant of a chip. This of course doesn’t happen in the wild.