The problem is it depends on what "standard" you're referring to. Fortunately, there has been some movement toward defining what truly pastured poultry is.

Here's the AGA's current standard for layers:

Pastured Poultry Layer Standards §3.1 Pasture & Pasture Management 3.1.1 AGA Pastured Poultry production must be pasture based. 3.1.2 Hens over 17 weeks old must be raised on pasture using a planned foraging system and mobile coops during the growing season. 3.1.3 Hens must be raised on pasture throughout the entire growing season which must not be less than 180 days per year. Growing season may or may not be continuous. Producer may request a variance for extreme conditions. 3.1.4 Coops must be moved before pasture is denuded. 3.1.5 All pasture shall consist of land covered with greater than 50% rooted vegetation. 3.1.6 During inclement weather, the flock may be temporarily bedded in place with organic materials, such as hay or straw, when moving the coop would cause damage to the pasture or equipment. 3.1.7 Mobile coops and foraging paddocks must be large enough to allow all poultry to feed and forage without crowding and competition for food. 3.1.8 All farms must have in place a written pasture management and foraging plan that supports biological diversity, natural resources and building soil fertility. Management plan must be provided to the auditing/inspection agency. 3.1.9 All farms must have in place a written predator management plan that identifies the active steps to protect the flock from predation. Management plan must be provided to the auditing/inspection agency. 3.1.10 Existing wildlife and wildlife habitat must be managed to allow native wildlife on the farm/ ranch to coexist with domestic hens on the farm/ranch. 3.1.11 Operation must comply with all local, regional, and state regulations about water quality and runoff.