We're pretty new to raising hens but decided learning all about them would be well worth it! We ventured out and bought 12 chicks; two of them turned out to be roosters. Our Light Bantam rooster suddenly has a large bump on his back more towards his left side. The skin is not broken but it does seem to bother him when touched. He started losing his tail feathers a couple of weeks ago and now has this large lump which has me worried. He's eating fine and has normal demeanor but I don't want to just go about business as usual. Any ideas on what it could be and what to do, if anything?