I try to get them out there every morning before I go to work even if it is extra work for me.
I believe it does them good.
For those who don't yet know,
For parrots like pionus parrots, who do not have a uropygial gland, being in "direct"sunshine (sun that is not filtered by glass or window) enables their skin cells to manufacture Vitamin D3 and this aids in calcium absorption.
Greys do have the uropygial gland.
This gland secretes an oil which is spread all over the feathers when the grey preens. The purpose is to help keep feathers supple and for waterproofing too.
When exposed to direct sunshine, the secretion on their feathers is converted to an active form of vitamin D, hence the parrot receives this vitamin by ingesting it when they preen.