What if chicken isn't laying eggs at all?

Answer 1

First and for most are the chickens female. Males/roosters do not lay eggs that is what a female/hen is for.
Secondly, the hens have to be old enough. At least 5 months old. I would not start worrying until they get closer to 1 year old. Different breeds start to mature at different ages.
If everything above is right then you have to look at everything else. Do the hens have enough space, feed, light, and water. Sometimes adding things to the normal feed helps, like adding some type of greens even if is lawn clippings. Plenty of feed and water is a must. When a chicken is in molt (loses feathers) it may take a few weeks before they start laying again. They will lay on the ground but many hens tend to prefer nest boxes, which can be made many diff. ways and out of diff. material.
This is just a little bit of information and not very easy to just type out. You just have to trail and error.

Answer 2

Several reasons could explain it. She may be too old and past her egg laying years, she may be a late starter if she is a pullet (under one year old).

She may be under stress or sick. You would have to give me more specific information for a more precise answer.