Drastic drop in eggs
We need more information. How old are your birds? Do you free range them? Give us a good idea of your situation so we can help you problem solve. It may be the light this time of year, but without more information, we can't analyze.
About how many hours of light are they getting each day? They need around 16 hours of daylight to maintain egg production. We are getting into that time of year when supplemental lighting may be necessary if you want to maintain egg production during the darker winter months. I live in North Florida, so we still get around 14 hours of light per day, and my hens are maintaining pretty well. I expect to add supplemental light in November, when it gets dark much more quickly.
The other thing that may be happening is that they are waiting for you to let them out to go and lay their eggs in a hidden nest. You should watch them - where they go and what they do for a good while when you let them out. Or, keep them locked up for a day or two and see how many eggs you get. That will help you determine if it's the light or if they are laying elsewhere. If it's neither of those things, then you may have other problems - mites, parasites, etc. They are too young to be molting, but it's possible that they may be starting.