Each spring I see countless cries for help from people with a day-old baby chick who is terrorizing the other chicks in the brooder, pecking at their eyes or plucking out their down. It's automatically assumed that this is a bad “egg” and the chick is evil. It's happened to me, and it makes you feel helpless when you encounter it.
Actually, it's not at all uncommon. Baby chicks have nervous systems and react to stimuli, and just like us humans, some are more sensitive than others and react with aggressive behavior when they experience these stimuli.
First of all, it's very important to rule out general environmental causes. A brooder that is too bright, too warm, too small, or too crowded will almost always result in some sort of unpleasant behavior. Rectifying these factors can correct the problem almost immediately. When that fails, there are several ways to deal with an aggressive chick.
While all chicks quickly learn to recognize the faces of their brooder mates, a chick can obsessively focus on any color, or size or pattern difference. It can get obsessive about shiny objects, and what's shinier than those shiny black eyes of its mates?
Some chicks become fascinated by the down on their fellow chicks, and may obsess over “tasting” and “sampling” it to the point of causing injuries, which escalates the problem. Any injury needs to be treated immediately before cannibalism sets in, which can involve more than just the problem chick. A product such as Blu-kote or Blue Lotion can camouflage the wound while healing it. In some cases, a badly injured chick is better off removed from the brooder until the injury heals or else it can also be the source of obsession.
If you're tempted to mark your chicks in some way, it's important that you don't artificially create “differences” that will draw attention and become a focus of obsession. Especially refrain from using anything red to identify any of the chicks. Keep chicks as uniform in appearance as possible.
When dealing with obsessive behavior in any age of chicken but especially chicks, the important thing is to diffuse the focus. You do that by introducing more of what the chick is obsessed with.
In the case of a chick who's obsessed with pecking at its mates' eyes, you can introduce shiny objects that will take attention away from the vulnerable eyeballs. Marbles scattered in the brooder, shiny duct tape stuck to the sides of the brooder, even little “bugs” drawn onto the walls all provide diversions and will diffuse the obsessive focus of an aggressive chick.
Strips of velour scrap or other fuzzy material suspended from overhead can divert attention away from the down of the other chicks. A mirror introduced into the brooder can make it appear that there are newcomers to be investigated, and it can occupy an aggressive chick's attention so it won't need to focus on its live mates.
When all that fails, and the behavior seems to be getting no better, there is one more thing you can do. It's worked splendidly for me when I've had aggressive baby chicks, and others have also reported tremendous success with this method.
You discipline the problem chick just as a broody hen or other senior flock members would deal with an unruly chick. You “peck” it on the back when it misbehaves.
Using your finger, gently poke the chick on its back the second you see it start to go at another chick's eyes or downy pelt. Repeat the “peck” each time you see the chick engage in this behavior, and if you can anticipate the chick's intention to go for an eye or pluck at some down, so much the better.
Chicks respond incredibly quickly to this discipline. I believe it's in their DNA to respond to behavior modification from their elders during these very first days of life. Therefore, it doesn't take very long for it to be effective and for the bad behavior to stop.
I mentioned in the beginning of this essay that this problem is not at all uncommon, especially in the first week after hatching. The good news is that most aggressive behavior of this sort will disappear on its own after the first week, and probably won't persist beyond the end of the second week.
However, it may be comforting to those of us who feel the situation is serious enough to intervene to know there are things we can do to restore peace to the brooder right away.
Editing this article to include some new information that has developed on a thread on the chick forum. https://www.backyardchickens.com/t/1141018/successful-reform-of-a-bully-chick#post_17734131 The OP reported that they had a very stubborn case of aggression that wouldn't respond to any of the recommendations in this article. After a week of removing the bully chick and reinstating it off and on repeatedly, it began to calm down, and by week two, it had become a normal baby chick.
I posited that perhaps an overabundance of male hormones was responsible for this aggressive behavior, and these hormones dissipated over the first week, returning to normal levels causing the chick to cease the aggressive behavior. There is a good argument here for patience and allowing time to correct the bad behavior.
Then my good friend Lazy Gardener chimed in:
"Interesting thought process, Azygous. Now, I'll add an other morsel to your hypothesis. If this aggression is caused by male hormones. I wonder if providing a diet rich in soy might alter the behavior. Soy is said to be a source of plant estrogens. Perhaps give the bully chick some tofu. An other thought: recently read study regarding color of LED light and it's affect on poultry. Blue LED reduces aggression. Wonder if simply putting a blue LED in the brooder might have a positive outcome."
So, now we have these additional tactics to pursue when encountering this frustrating problem! Please report back here on your results if you try any of these techniques! We will all benefit!