What breed of quail do you have? Quail are seasonal layers (meaning if left to their own accord, they will only lay during their breeding season of spring thru fall) and wont lay in the winter unless you add more lighting to their environment. (12 to 16 total hours of daylight)
Especially if you have one of the New World quail breeds (which does not mature until they are 6 or more months old) such as Bobwhites, Gambels, Blue Scale, California's, etc....they are notorious on waiting til the following spring from their hatch, even with added lighting.
Stress will prevent them from laying as will being ill of health. The improper ratio of males to hens, depending on the breed, will also prevent laying.
Make sure you have them on a good diet, and always offer up crushed oystershell to the layers.
