The birds will soon go into moult. For a month, laying will be almost nill. The second laying season, the birds will often lay 25% less so the economic numbers have been crunched and the poultry company has decided that "All old out" and "All new in". In other words, they'll replace the entire flock with pullets at point of lay for their next 10-12 months of egg production.
This is fairly common in the table egg industry.
You should also know that the highly specialized commercial layers used are bred by Tetra to lay up a storm their first year and such birds often burn out at 2 years of age and do not lay well subsequently. They weren't designed for the long haul. They've largely been bred to best match the practices of the poultry farm's needs.
Hope that helps.
There are the usual concerns about disease whenever you bring new birds into your homestead. In the case of highly secluded and shielded commercial layers, they may not have great disease resistance to things found at their new place. Just something to consider.
