This is 1 of 14 chickens my hen hatched in January. And the only one different. She had an underdeveloped wing, has crooked toes, and never had feathers on this spot and similar on other side! Other than that she is a very healthy happy hen! I've tried to search similar photos with no success so decided it's time to ask someone!
What could have been the cause of these? Im really curios though about her baldness!
Hunt County Texas
Most likely just a genetic defect, as long as long as the bird can eat, drink and move freely without pain as it appears she does and you don't feeding a bird that may not be as productive of a layer just enjoy the diversity. I would recommend that she not be bred to produce fertile eggs as the chances increase for more genetic defects in her offspring.