Hens that are bred to be very productive layers can and often do, develop internal laying and other issues when they stop laying eggs regularly. Keeping those hens alive and as pets after their productive years can be as cruel as the kindness intended, unfortunately. I recently read this rather eye opening thread on the topic on one of BYC's sister forums:
https://www.sufficientself.com/thre...-they-stop-laying-warning-graphic-pics.15366/
Mind, there are graphic pics in the thread, but it's very interesting and educational and well worth a read.