I have 13 girls all around 6 months of age and I have been getting 5 - 6 eggs per day lately with all of the girls acting and doing normal chicken things. They free range during the day, are fed FF and all have been acting normal. Up until yesterday that is; I noticed one of my black stars, who is always very active and one of the top layers, was kind of acting depressed and keeping to herself. After a day or so it seemed like she was acting better so I let it be. This morning when I let them out to free range she came out but went off by herself and stood alone, with head tucked in her wing. She's definitely not acting normal that's for sure. I noticed her butt is messier than normal too. However, two of my BR's have had messy butts the last couple of days but they are still acting normal. The other thing is , they aren't eating their FF like they normally do... Usually when I put that stuff out it is gobbled up within minutes but the last few days I can fill their trough with FF during the day and the next day it is still half full. Even while free ranging thy ALWAYS cleaned the FF dry. To note, I recently (1 week ago) added a 5 month old rooster to the flock, he too seems to be acting normal with no signs of illness. I got him from a man with a small flock who ended up with. 4 roosters and of course e wanted to get rid of some. I'm worried about the black star and am wondering what I should do to treat her. I have separated her from the flock and given her some dry feed and ACV water. Could this be vent gleet or something , coccidiosis, etc ? What should I do about the other two BR's or have messy butts but otherwise seem to be acting normal ? Also, I am now only getting about 3 eggs per day, down from 5 - 6. I find this a bit stressful and am hoping that someone can offer some advice. I don't understand what's going on or why their appetites aren't what they used to be.