How do you turn a fridge egg into a chick?

You can't. For an egg to hatch into a chick it must be fertilized by a rooster. This occurs before the hen ever lays the egg. Eggs which end up in egg cartons are carefully processed, having been laid by hens which do not have access to a rooster (unless they are free-range eggs purchased directly from your local farmer). They are not fertile, and have no chance of ever hatching.