I give mixes that don't contain them.
Best advice that can be given about diet!!!
I have always fed a main staple of a Natural pellet
AND supplement the pellets as the main staple with a healthy, low-fat, varied Seed-Mix
that contains no sunflower seeds at all of any kind (regular, black-oil, etc.), as well as no nuts of any kind. Bird's bodies, specifically their GI Tracts, are designed to eat seeds and grains daily, so feeding them a small amount of a healthy, low-fat seed-mix every day is good for not only their physical health, but also their
mental health. Pellets are healthy for them, yes, because they provide the perfect amount of all nutrition they need daily...However,
pellets do not exist in nature, and as such, bird's bodies nor their minds are not meant to be eating them and them alone. They need to eat seeds, grains, legumes, etc. to keep their GI Tracts (gizzards specifically) healthy, and keep their innate need/want to eat these pulses satisfied. The key, as Noodles wisely mentioned, is to ONLY provide captive birds with a healthy, low-fat mix of seeds, grains, legumes, etc.
Sunflower seeds, any type of sunflower seeds, as there are many, the common ones in parrot seed-mixes are the regular black and white striped ones and then the black oil ones, provide them a lot of protein, they aren't without their good properties. However, they are extremely high in fat, and the number one reason that captive birds develop early Fatty Liver Disease and die long before their expected lifespan is due to them eating fatty seeds and nuts every day. They aren't wild birds, so they don't have the same protein, fat, carb, etc. needs as wild birds who fly an average of 10-20 miles every day do.
There are plenty of very healthy, low-fat seed-mixes out their that contain no sunflower seeds or other extremely fatty "junk" seeds, no peanuts or any other nuts, as well as NO CORN, but do contain a healthy, low-fat mix of seeds, grains, legumes, dried veggies and fruits, etc. Some of the more common brands/mixes include Tropimix (which also contains Tropican pellets in it), Higgins VitaPrima mixes without sunflower seeds (their VitaPrima California Blend is excellent), Sunseed VitaSeed without sunflower seeds, among many others, It's all about reading the ingredients...If you look at a seed-mix and it contains ANY types of Sunflower Seeds, Nuts, or Corn, DO NOT BUY IT!!!
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If you don't give it to your bird, they can't eat it!!!****
****A great way of looking at this seed-mix thing is like this:
-Cheap, junky seed mixes (as well as a lot of expensive seed-mixes) contain Sunflower Seeds, Safflower Seeds, Sesame Seeds, Peanuts, and Corn...
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The types of OILS THAT WE COOK WITH/FRY OUR FOODS IN INCLUDE Sunflower Oil, Safflower Oil, Sesame Oil, Peanut Oil, and Corn Oil...
-Oils = Fat, and Fat is stored in the bird's liver...
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Fat stored in your bird's Liver = Fatty Liver Disease!!!