Here are the regulations of the National Organic Program in the United States:
http://ecfr.gpoaccess.gov/cgi/t/tex...2&tpl=/ecfrbrowse/Title07/7cfr205_main_02.tpl
Of note to poultry and laying hens:
Chicks needn't come from organically raised parent stock. Chicks must be fed organically from the the second day of life. (The first day they are considered to live on the yolk from the parent hen, which isn't necessarily organic). If they are ever fed non-organic, conventional feeds (this could include your kitchen scraps) then they are not eligible for organic production.
Layers must be provided access to the outdoors, depending on stage of life and outside weather conditions.
Any pasture must have been managed organically for at least the previous three years. If you have sprayed weedkillers or spread synthetic fertilizers then that pasture area is ineligible for use in organic production until three years of organic management. Any replanting while under organic management should use certified seed, if available.
They must not be given synthetic (or even some highly processed natural ingredients) antibiotics, wormers, certain electrolyte mixes, etc.
Sick birds should be removed from production and treated. Once they have been treated with non-organic inputs they are ineligible for organic production.
Any bedding that they may eat must come from certifiable organic sources.