New kittens and their mom

Question
Our cat currently lives in our backyard with her 3 week old kittens and she won't let us move them. They have always stayed in one spot with their mom, but recently the mom has been moving them around, mostly in boxes in the corner of our garage. Is this normal? And if not what should we do?

Answer
It is often the case that a mother cat will move her kittens in response to a threat either real or perceived. Is mom a feral cat? If so you may want to consider the use of a humane trap to trap her (use tuna, soft cat food, sardines, anything that is high in smell and irresistable to a cat). If you are planning to keep mom and babies you will have to consider making a vet appointment and having your little family checked to ensure that they are healthy. If mom is feral and you are bringing her and babies inside make sure it is to a quiet room with less human traffic and that other household pets do not have access to. At three weeks of age kittens have an immature immune system making them vulnerable to disease and infection. The kittens are also at a very critical point in their social development. They need to be handled to ensure that they will make good pets.
If mom is not feral it is still a good idea to bring her and babies inside to ensure their health and socialization. If mom decides that she doesn't want to come in try the humane trap and gather the babies. You may want to use leather gloves if these babies have not been handled before as they will have extremely sharp claws and will be very fearful. Either way the kittens should be vet checked relatively soon just to be sure that everything is progressing as planned. Once you get mom inside the house DO NOT let her out as she may not come back until she is pregnant again leaving you to raise her babies by hand. To help curb overpopulation you may want to consider having mom spayed once her kittens are weaned and her milk dries up (8-12 weeks of age) depending on mom.
As a sidebar mom and babies should have water and a good quality kibble available at all times, if you want to stimulate interest in food in the babies making portions of soft kitten food available for a short period of time several times a day will eventually give them the idea, but most likely you will start noticing that the kibble is disappearing more quickly and there are little poops and pees in your litter box (you need one with really low sides to facilitate litter training in the kittens). Given the opportunity mom will teach her babies what to do.
If I have not adequately answered your question feel free to ask another and I will reply as promptly as possible. Good luck with your new little family!