My girlfriend has a green cheek conure, and we recently noticed that she started having these small black feathers in spots. I'm just curious if this is anything that we ahould be concerned about? Or if its natural. She's about 4 years old
Feather condition, color and replacement is commonly a reflection of its health and diet over the proceeding six plus months. The mineral contain of the diet 'may' effect color on new feathers, but that is normally a variation of the normal color not a total change in color.
From time to time, DNA may push an odd color in an area that would be unusual. It just happens. It is also just as possible that a color may have transferred from a toy, food, etc...
From the looks of it, she seems to have a few stress bars. As SailBoat mentioned, feather condition is a reflection of the past few months. All stress bars indicate is that, at the specific moment in time that particular feather was forming, your girlfriend's greencheek experienced something of a stressor. This might have been a major change in environment or circumstance, a traumatic event, an illness, or a less than ideal diet.
All that said, however, there really aren't very many of those marks at all. If any of those causes match anything that has occurred, addressing them should head off the development of more stress bars.