Parrots can look immaculate and still be sick. My first bird, also a blue front, passed away when only 5 years old. To make a long story short, he was a wild-caught baby (this was back in the early 1990s) who must have brought something with him that went undetected until I noticed he had a weird twitch, prompting a physical. By that time, his illness was past any chance of treatment, and I lost him a few months later. I took a picture of him on his last day -- if you saw it, you'd think "what a beautiful, healthy-looking bird!" Meanwhile, his necropsy showed how he was ravaged internally from the effects of a cardiac infection and subsequent liver failure.
Moral of the story -- healthy-looking does not mean healthy when it comes to parrots. When getting any new parrot, it's wisest to bring it to a vet for a complete physical. Expect the bill to be a couple hundred dollars -- they will take fecal and blood samples, and choanal and cloacal cultures to make sure nothing is simmering below the surface. It's wise to repeat these tests annually so you can get a head start on knocking out anything before symptoms show -- by which point, it's usually too late.
Sadly, I knew this even when I got my first bird, but being a child, I didn't have control of my money, and my parents wouldn't let me bring him for a proper physical. When I was old enough to take care of things on my own, I found another amazon (this time a double yellow head), and Sammy and I have been together ever since. When I brought him home, an appointment was already made for his physical. It turned out he was calcium-deficient and overweight (consequence of a mostly "parrot seed mix" diet), and had a lingering but mild bacterial infection (which he'd probably shake off easily if he wasn't on such a crappy diet). After a change in diet and a course of antibiotics, he improved quickly. He was 7 when I found him, and he'll be 24 next Spring. Oh, and don't fall for the "you have to get them as babies if you want them to bond to you" baloney. Sammy latched on to me big-time, over our first few months together. He follows me around the house and calls me by name whenever I'm out of his sight.
Here's a pic from this past Winter. He flew over to sit on my leg while watching television, as he does every night.
We have a DYA, too! He's a rescue. The first thing people say is, "Wow, you got him for free!" Nothing could be further from the truth! When we found him (outside) we got him into a cage and brought him to a vet that would see birds (only 2 in Jax) that was available soonest to get him looked over. (At this point we were looking for his owner, and trying to make sure that he was ok, since he had a large chunk missing from his beak, as well as very overgrown claws.) So we paid for the initial visit, but then also had to go to the pet shop to get him some larger food. (Our biggest bird at that point was a Quaker! He looked funny eating tiny quaker pellets, lol!) We kept searching for his owner, and after a month or so found no one to be searching for him. The vet bills (he later went to the avian specialist for blood work and micro chipping and meds) from the first couple of months were close to a grand, not to mention larger cage, toys, food, etc. He was in relatively good health, all things considered, but had a minor mutilating tendency that had to be treated, minor skin infection, vit A deficiency (probably from a seed diet, the vet said), and a beak in need of healing. It's been almost a year now and he is in very great health, but always get the vet records. If there are none, I would be very hesitant to "pay" anything.