This comes down to "when do I change the litter?"
I'm not going to ask how often because I know that depends on the number of chicks (5) and the size of the brooder (20-25sqft or so), the type of litter (pine shavings), depth (currently 3"), etc. What I'm going for is sort of: how poopy should it look? Five minutes after I put in a new layer it looks at least kinda poopy, but a day later it doesn't look all that much poopier because they're working the old stuff down. So maybe what I'm trying to ask is "what percent poop" am I aiming for, int he sense that if I take a random scoop and look at it, how much poop should I see? 1%? 5%? 50%?
Sidenote: I enjoy catching bugs for them to eat, but I'm pretty sure they lose calories on it since whenever I throw one in, a chick will pick it up and then run around like crazy for the next minute or two trying to escape all the other shameless thieves she's suddenly surrounded by.