Respuesta :

A group of kittens is called a kindle. The word "kindle" comes from the Middle English word "kindel," which means "offspring." It is derived from the term "kindelen," which means "to give birth to."

~and also called cute :P hope this helps 
If they're all from the same mother they can be called liter of kittens....... Other that I'm pretty sure they're just called kittens. Or baby cats.