Production hens, like white leghorns, red-sexlinks (ISA Brown, Golden Comet, and a number of other breeds) are bred to give one egg a day. But they often die of reproductive issues or cancer around 2-4 years old. A production hen that lives to 4 years old or more is really old. Even the...
Around 18 months, most chickens will have their first molt. If they are gearing up for that, they may stop laying for a few months. You may see feather loss, or they may eat the feathers.
If the hens turn broody, they may stop laying eggs, but you'll see broody behaviors also.
If you want to...