All set to worry

One of my babies had a dark spot on its back when I examined it it was just chicken **** but I was concerned about the red spot it was leaving under it I cleaned it up and there was feather loss and maybe a little bit of the other chicks picking. But this one one of my 2 chicks that are almost twice as big as the others so I was hoping bullying would not be too bad. I have only had them a week and a half- less than this when it happened. She was fine Sunday and Monday she had this sore, Tuesday it looked bad but no broken skin, yesterday I looked over the meds available at tcs and made sure it was clean but it looked a little better and today I was going to ask what if anything I should do but...... IT healed all on its own in 3 days!!!!!! I am so happy I was torn I know they need to establish a pecking order and If someone gets sick to remove them but she and her sister are normally my bullies so I waited and her feathers are already looking better and no more pink