But not all cats try to hide their kittens away, although in a very comforting environment for the mother, she would still move them around. Probably when you leave you make too much noise and the mom decides to move them away. Maybe if you always leave at a specific time, the mother would learn your routine and thinks that with no one at home, it probably going to be her best chance to take care of the youngs while the pesky human is gone. Whenever she feels a sense of danger too, she will promptly move them away. So respect her space for the time being. When the kittens get older she might start trying to find them a new nest, closer to the hunting ground if it's in nature. The mother might just go off to teach them how to hunt, or eat the solid canned food in this case. There is probably nothing to worry about. But if she continues this behavior for a long while, then maybe it’s about time you regain the trust with her.