Wings

Wings can appear at any stage of development between early teens and late 60's, but most typically in the early 20's, and develop over the course of about a week with very little warning beforehand.

Signs of impending wing growth include unusual protein and mineral cravings, back and shoulder aches, itching, and fatigue. A person should seek treatment if these symptoms persist for more than 52 hours (2 days). During the growth period they'll need to eat well, manage the pain (magically and/or chemically), and avoid injury to the back, which will be especially tender and slow to heal from any extra damage. Bed rest is recommended.

Wings don't start growing in anyone too malnourished to survive the process, although in borderline cases they can leave a person with vitamin deficiencies.

Aside from “gets enough nutrients,” the development of wings isn't correlated with any other known factor, including race, sex, diet, magical powers, or environment.

Once grown in, they behave as fully functional limbs, although they aren't large enough to fly with. They can be treated by a human doctor with special training, or, in a pinch, a vet who has experience with flightless birds. (The wings of flight-adapted birds have different adaptations.)

They don't have any special powers of healing or regeneration compared to other limbs; that is, if a person's wings are amputated, a new set will not grow back.

The feathers are almost always naturally white, with rare exceptions that are black or patterned. Like hair, they can be dyed.

In most countries, any largeish town will be able to support services for winged people: feather stylists, tailors to alter their clothes, doctors who specialize in wing health and anatomy, and so on.

In Sønheim, wings are seen as a sign of the favor of Queen Szélanya (who has wings herself, usually depicted much larger-than-life). It's common to unconsciously treat a winged person with a bit of extra respect and deference.

If a winged person experiences any discomfort or difficulty adjusting to their new limbs, the perception is “that's small price to pay for all the luck you just got.”

In Ceannis, employees are entitled to paid time off for wing growth, and adaptations like “cutting holes in all your clothes” are covered by national health insurance. In the rare case where the person feels persistent dysphoria or dysmorphia about the new wings, the feeling can be treated like sex-related dysphoria, with surgery provided as necessary.

There are probably places where wings are seen as unlucky, and either hidden or routinely amputated at the first opportunity. Hopefully those will never come up.