That does look concerning to me...but I am not a vet.
I would definitly get them to a CAV (avian certified vet).
Have you had blood work done?
Do they have access to any metal objects that are not made of stainless steel?
How long have you had the bird and has the poop changed?
How long have you been feeding that? It's really an unhealthy diet and completely lacking in nutrition while very full of fat.
You shouldn't cut them off cold-turkey (because a stubborn bird can starve), so you should keep feeding some, but try to slowly wean them onto pellets and fewer seeds-- sunflower seeds are like crack to them and they really don't have much in the way of benefits. Do try to give lots of safe veggies as well and fruit in moderation...