I'm familiar with the fact that a hen will attack chicks who aren't a part of her brood, but I am curious about how some of your cocks deal with chicks. Do yours go out of their way to attack fluff balls, or will they generally ignore them?
My Asil cocks don't care about them - any chick can pop in, they ignore it. I have seen some larger ones though - that acted exactly like Bull-god's post. They looked at any small moving thing as "trick or treat." In my yards and in my experience, the larger the Asil/Oriental type, the more likely to try that.