Do I increase cook time when roasting 2 chickens at once

My Greek Yia Yia roasted two chickens stuffed with lemons and garlic from her garden every Sunday. She always said one chicken looked lonely to her. :) She always started the oven 25° hotter and then turned it down when she put the chickens in. I don't think it's at all necessary, but my Mom and I still do it because she did.

It should take roughly the same amount of time, though you should test each separately for doneness.

You shouldn't have to, but you should check the internal temp of each one before you remove them from the oven. I love my thermopen for that.

You shouldn't have to--just make sure there is space around both of them so the heat can circulate.