I’d heard that seeds are fatty and can cause issues. And Wink won’t touch veggies, I’m working on it. He seemed afraid of the collard greens I offered him this morning
Light coloured seed (cream or white) is low in fat and is more carbohydrate.
Dark coloured seed (brown or black) are oil seeds and have a lot of fat in.
If you feed a varied diet with a mixture of these seeds, the birds are fine. I used to increase the amount of oily seed in winter and during breeding so the birds could gain a bit of weight. But they do need some all year round. As long as you don't buy packets of oil seeds with no carbohydrate seeds, the birds will be fine.
The other thing to do is make sure they eat most of the seed before you replace it. Some parrots will eat all the sunflower seed as soon as they get new seed. Then they won't eat any other seed. If the owner replaces the seed each day, the bird simply eats more the sunflower and leaves the rest. Eventually the bird gets fat and has nutritional deficiencies and dies from a heart attack or fatty liver disease. This is more common with larger parrots and cockatoos that are kept in small cages and don't get any exercise.
If you get the bowl of bird seed and take it outside, you can hold it above an empty container and slowly pour the seed into the container. You can gently blow air over the seed and it will help remove the empty seed husk and the good seed falls into the bucket and can be re-used. Do this 2 or 3 times to get rid of most of the empty husk and put the remaining seed back in the bowl for the birds.
If most of the seed is gone, then replace it with fresh seed.
Most bird seed has a mixture of carb and oil seeds (about 90% carb and 10% oil). This is fine for warm weather, but you can increase the oil in colder weather, if the birds get regular exercise.
If you offer smaller bits of green feed, the bird won't be as scared of it. Birds also learn from each other so if the new bird sees the older one eating greens, the new bird will be more likely to try it.
Offer a wide variety of fruit and veg to the birds.