This may have been already asked, if so I am sorry for asking again. How often do you OT sell out your old layers and replace them with chicks? Do most keep them until they die or do they sell all their layers every year or every 2 yrs and replace them with their offspring?
A.T. Hagin writes on another thread:
In a hen's pullet year (her first lay cycle) you will get 100% of whatever she is capable of laying in a year assuming proper feed and management. She should start to lay at about five to six months and will lay typically for a year which will take you up to the eighteen month mark.
At that point she needs to molt and refresh her egg laying internals. Once she's grown out her new set of feathers she should begin laying again. All other conditions being equal (disease, injuries, feed, management) she should then lay roughly 80% of the eggs she laid in her pullet year in her second lay cycle, but those eggs will be somewhat larger. So if she were laying large eggs in her first year you should get extra-large in her second.
At the end of another twelve month cycle she will then molt again then restart laying, but about 20% fewer than the previous year or roughly about 60% of what she laid in her pullet year.
Lather, rinse, repeat.
If you're keeping the birds as livestock that have to show economic practicality (as in pay for themselves) then chances are by the end of their second lay cycle they will no longer lay enough eggs to cover the cost of their feed so it will be time for them to ship out.
If you're keeping your birds as pets as in they don't have to lay enough eggs to pay for what it costs to keep them then you may keep them as long as you please.
Historically the poultry keeping model worked like this:
All through the year a poultryman would give his birds the visual once over to remove any obviously sick and otherwise non-productive birds. When the birds reached the end of their first lay cycle and were ready to molt the entire flock would be given a closer inspection. The non-thrifty birds would be culled and the remainder kept for a second year. Typically about half the flock would be culled and new birds brought in so you'd end up with about two-thirds first year layers and one-third second year. At the end of their second year the older birds would be culled unless the farmer was doing his own breeding. Then the best of the older birds would be retained for that purpose.
This is where the "get rid of them at the end of eighteen months" advice comes from. Whether it applies to you only you can decide. Some folks don't care, others must weigh the cost of feeding non-productive birds.
Edited by A.T. Hagan -