I call that 'toothsome'We dispatched them around 20 weeks. They weren't tough but kind of chewy so I dnot know if I want to go that route again.

Even well rested 16 week old grilled cockerels are toothsome.
Did you rest the cleaned carcasses for 48-72 ours before cooking or freezing?
Have you ever eaten a layer breed before?
How did you cook it?
No layer breed, at any age, is going to be as tender as an 8wk Cornish meat bird.
Had some BCM over OE cockerels this year, they were of good size and delicious, but not incredibly tender.