I watched a documentary a few months ago about chickens gender changing, however, its only in appearance, although a cockerel will no longer crow and the hen probably will crow and a hen changed into rooster can't fertilise an egg nor can a rooster changed into hen lay an egg and according to the documentary it isn't life threatening nor harms the bird. Having said this though, I'm thinking, maybe could be like us humans who can take on opposite gender appearance i.e. I am 55 never had facial hair but recently have started growing hair on my top lip (thank goodness for hair removing products!) and my late grandma had hair grow on her chin, to the amount of looking like a small beard. I've seen elderly ladies with sideburns, beards and mustaches! Either way none is harmful to the bird - or humans for that matter