Vermicomposting, worm bin, composting with worms community and forums
Earthworms release an "Alarm Pheromone" when they get stressed or over populated. It serves as signal to flee or stop reproducing. They also have good pheromones that say "follow me to food" or "let's have sex." I guess it's best to thin out the herd before the alarm pheromone gets into the bedding.
i think its about 1000 worms per sq ft if there is food available