Elderly leghorn started laying again

[caulichicken]

My elderly (6-7 yo) white commercial leghorn has not been laying eggs for a few years now. Suddenly I am getting an egg a day from her. So any idea what would change to make her lay again? I've also noticed a buff (who is at least 10 years old) is now sitting in the nests. I'm not sure if she's laying eggs or not though. I give the hens a bit of a break during the winter with light (only turn it on at 6 am until the sun comes up and then no supplemental light in the evening.) I'm in western Canada.

 

[sourland]

Good for her. She's an overachiever.

 

[nuthatched]

Sometimes elderly birds lay here and there, I wouldn't expect it to last long.