I am new to BYC and I need a little help or at least some suggestions. I was raised on a farm and my husband and I got an opportunity to have a small flock of chickens since I cannot have any other agriculture animals. I did quite a bit of research I thought I had done enough but maybe not. We settled on Rhode Island Reds for three reasons they are suppose to be able to take the temp. change here in Florida, and my husband had them when he was younger I grew up with White Legghorns. When we bought the birds there was one that seemed to be not as energetic as the other two as time went by I just thought that was her normal. Then when I went out to open the coop door to let them out one morning I had a dead bird, not the non-energetic but healthy one that hung out with the slower one (Racheal). She had no signs of sickness so I thought maybe she fell off her roost and broke her neck? Two weeks later Racheal got very lethargic she was eating, not great, and drinking well the only issue I saw was that her stool was yellow in color but not runny. Four days later she was dead the last stools she had were very running, brown and stinky and one that was black and tarry again runny. What am I doing wrong I give them good food, grit, oyster shell, a little scratch and a few mealworms. I keep there water clean with vitamins added to it. I am on well water. I do not free range them because there are a lot of hawks here and I did not want to lose my birds to a predator so they are in an enclosed coop. Small birds can fly into. The coop area through the wire. A couple of days ago I brought home two more eight week old birds, they seem very healthy and I have them penned off from the others or I should say the other one. I do not want to lose any more birds and I really need help, suggestions or any useful comments. Maybe I have overlooked something. Thanks for your time and posts in advance.