A hen's incubation is exterior rather than within her body, but her babies still need her body warmth to develop or they will die of hypothermia. In the absence of a mother hen, we use artificial incubators. Even with an incubator, though, the embryos still need the incubation to be constant and correct in order to develop into chicks, whether it's incubation from mother hen or from a nice Brinsea incubator.
Since you're not familiar with how to successfully incubate chicken eggs, before you start, you will want to read our free guide to incubation and hatching.
Before you make a decision whether to pursue home hatching hatching or not, you will want to understand how it works, how likely the eggs are to hatch, how carefully you must maintain the incubation environment (even a difference of one degree Fahrenheit can have a profound effect on your success), and what the results may be. You will also want to compare home hatching to starting with baby chicks, since it is almost always less expensive to start a flock with already hatched chicks. Remember, chicks have a live arrival guarantee, and you can choose whether you want males or females, too. You just can't do that with eggs! Fertile eggs (from any source) are not guaranteed to hatch, and you will always hatch a straight run mix of male and female chicks.