Current issue: Black star chicken roughly 6 months old. Has been about 36 hours with less feathers due to another chicken pulling feathers; temps 50s day, 30 night; has had Pine Tar on. This morning noted very small amount of poop under roost, unusual. Had electrolytes yesterday in water, has been fed mash/tuna/cottage cheese/sunflower seeds/freerange. Today did not seem to eat/drink very much. No egg. Seems to shiver (?) a little bit, vent pulsing in and out and sticking out of body. She also seems concerned with her butt, trying to reach it by bending around and between her legs to reach it; seems to be cleaning her feathers/preening although area covered with pine tar? Should I be concerned? Backstory: Above story is about Chicken #3 (C3). After a dog attack, I was left with only chicken #1. So I obtained Chickens #2 and #3, who had a hard time getting along with C1. C1 spent a lot of time alone out of the coop free ranging due to no other way to separate flock adequately. C1 never laid, had pale comb, maybe had difficulty growing, pink long/flat thing in poop every morning (tissue?), otherwise seemed fine. C1 then had down-pointing tail feathers, so I decided to deworm all three birds this past Monday. C1 went out after deworming and never returned from free ranging, never found body, assume she is dead. Same day of deworming, C2 decided to start pulling feathers off C3, and eats them (I assume, as I see none laying around). Within 24 hours, despite allowing C2 and C3 to free range all day, C3 was naked down entire back and some near tail and back sides. I applied BluKote, Pine Tar, gave electrolyte water, clipped both birds' beaks, and gave protein (tuna, cottage cheese, refed own eggs). Despite this, I noticed more butt area feathers gone this morning, so separated the birds - C3 in coop, C2 in range pen (despite temperature). C3 was free ranging the last couple days out in the rain and temperatures as indicated above and seemed to tolerate it fine. As of yesterday, both birds were laying great eggs with solid shells. I did turn off their night light as of yesterday, in order to encourage them to molt so that C3 has feathers during the winter. I turned it totally off, not sure if that is too abrupt. Thanks in advance! This is all such new stuff, I can't believe the difficult fall I've had with my chickens!