BOs are generally known to be fairly calm chickens. however i had some BO roosters and they were mean and aggressive. i had to cull them early as one of them attacked my 68 pound airedale terrier unprovoked(didnt end well for that one) i have a scar on my leg from a sneak attack from one...
sorry about your chicken. but they can just die. it could be any number of reasons why this happens. if the chicken appeared healthy at least you know it isnt some disease that will spread through the flock.
i generally stick with chick starter grower food only until 8 weeks. then food scraps of any kind are fine. just make sure chick feed is primary diet still
i only turn the twice a day and have had 100% hatch rate for my last 2 hatches of 20 eggs each. steady temperature more important than turning eggs. i believe hens roll eggs around in nests to move outer eggs in and the inner eggs out to keep inner ones from getting to warm/outer ones too cool...
i use an out door electric heated dog dish for water in winter. its fairly large holds about a gallon of water. i also use 10 pound feeder for food. i keep food water in the run area which is fine it is covered and dry. it keeps the coop cleaner just make sure the food doesnt get wet or it will...
i had one hatch with that same problem once. it took a while maybe 8-10 hours after hatch for it to walk normal. it is fine now and one of my biggest baby chicks
did you candle day 3 or 4 thats best time to see veins. day 8 or nine it does look like solid mass which is a goo thing. by day 13ish that mass will be bigger and/or harder to see through egg which would be growing chick