I've got hens that lay eggs that are a nice, pretty medium brown - but a month ago, when I wasn't getting any eggs at all, I was forced to buy a dozen from the grocery store (ugggghhhh). When I opened the cartons to check for cracked eggs, I was taken aback by the "brown-ness" - they were SO brown, they almost didn't look real!!! This was at a local Safeway store, and the brand was Lucerne.
I still had a couple of the Lucerne eggs left when my hens finally started to lay again - and when I put a fresh one in the fridge with them, it made the Lucerne eggs look like they were brick red! Seriously, they looked like they might have been dyed! I was thinking maybe they were from Welsummers, but I heard they're not reliable enough to be considered a "production layer"?
ETA: I don't have any hens that lay double yolkers, but years ago, I got an entire dozen of double yolked white eggs from the grocery store!