Need some help here guys. I am new to chickens and just got a flock of 25 3 day old SS chicks last Sunday. Everything went great up to yesterday morning when I woke to find two chicks dead. After some research and posts here I have concluded that they were killed by the other chicks, pecked to death around their vents. During the day yesterday, I kept very close watch and saw this happen to two others in the flock so I had to separate them from the rest. They are doing fine now and are recovering nicely since I caught this in time. Yesterday afternoon, I reduced their temp from 95 to 90 (i'm using a 250w red heat lamp suspended about 2' overhead), cleaned the cage, changed their feed from 20% to 24%, added a pecking block to the brooder to give them something to peck at, and added save-a-chick to their water. I did all of this with advice from the breeder I bought the chicks from and from advice on here. Their brooder is 3' x 6' so they have plenty of space, and they seemed nice and happy last night when I went to bed. I woke up this morning to find two more injured chicks, one bleeding from the beak and the other was being attacked by many other chicks around the vent and it was very bad. I isolated them as well, however the last one did not make it, it died a few minutes later. While watching the flock for a while this morning, I saw that one chick in particular was harassing the others, while most of them just scratch , eat, sleep. It would continually walk around and grab the other chicks by their butt. I put it in with the isolated chicks and it immediately started harassing them as well. I'd like to mention that I have 3 chicks isolated by themselves and even though they are injured they do not harass one another at all. I assume the one chick is being a bully, so I quickly isolated it to a different brooder this morning before I left for work this morning. So, ultimately I'd like to know if I am doing something wrong here, or if I just have a bully chick thats injuring others and inciting a riot when injuring the others? If its a bully chick, will isolation change the behavior or should I cull it now for the safety of the rest of the flock?