I heard my chicks raising cain, and went to see what was wrong. One of my kids got the bright idea of putting on of my daughter's small elastic ponytail holders in the brooder (it was small enough for them to carry, but big enough that they couldn't swallow). They were playing keep away. Occasionally 2 would get ahold of it, and it would look like 2 pitbulls fighting over a bone. The chicks are between 2 days and 2 weeks old, and they kept this up for hours.