yup. In some anyway. I got a box of 25 PBR from Murray McMurray a years ago for my brother..he was just starting out and after a few weeks he changed his mind so I sold the pullets off, but those PBRs that Murray McMurray sells are Jumbo egg laying machines and just super pleasant birds. Their type looks pretty good, but the barring is not like the quality breed shown in the standard.
So they do have some qualities left, and egg production I think has been purposefully bred into hatchery birds, like Saladin said, some were not meant to lay alot.
But they would not be able to sell their birds if they did not lay gobs of giant eggs, that is what the hatcheries are all about= Give the consumer what they want, and what they want is eggs and meat.
We poultry conisours (sp?) are the ones who want the bird to be as the standard says, the general not knowing public just wants breakfast.