Chick is acting "normal", eating, drinking, pooping etc...but keeps pecking under her/his wing. I'm a complete newbie with chickens, they all have been great so far. No other looks like this, but the others(total of 9) sometimes rub their beaks under there wing. Is it normal behavior? The pics below don't look normal. Any help would be appreciated. Pic was taken last night, chickens acting "normal" this morning.