Hi ZivaDiva,
According to my research all birds, but greys in particular are perhaps a little more sensitive to the low level of V-D3, which is produced by sunlight.
So if you are in an area where you can offer natural sunlight year around then I recommend to take your grey(s)out for at least 15 minutes every day, if this is possible. V-D3 is necessary for calcium assimilation.
If it is not possible to take your grey outsite and/or during the winter months, you can offer Stonyfield (organic) low fat plain yogurt, which is fortified with V-D3, about 3 times a week, the amount is small, like 1/2 of a teaspoon.
Also, you can supplement your grey's diet either with flax seed oil, or unrefined red palm oil, about 1/4 teaspoons everyday.
I personally prefer fresh palm nuts, which I buy from a Florida orchard. I give my greys, 1-2 every day.
You can also supplement his/her diet with Alfalfa powder, which you can purchase in any health food store. The recommended amount is about 1/4 capsule, a dash on the tip of a knife, daily. Mix this into the food. Alfalfa contains lots of minerals, vitamins and phytonutrients.
The above suggestions are for parrots who eat only fresh foods and seeds, not pellets!
Pellets are already fortified with all these supplements!
Warm regards,
Marianna
http://www.juliascountrypantry.com