Bug zappers might make a feast for your chickens, but they won't take care of the biting flies, gnats, and mosquitoes. I had one, and I only left it up for a week. Most of the dead bugs I found in the tray were green lacewings, a beneficial insect.
"In 1996, University of Delaware researchers Timothy Frick and Douglas Tallamy published a study in the journal Entomological News. They had collected and identified the kills from six bug zappers at various sites throughout suburban Newark, Del., during the summer of 1994. Of the nearly 14,000 insects that were electrocuted and counted, only 31 (0.22 percent) were mosquitoes and biting gnats. The largest number (6,670, or 48 percent) were midges and harmless, aquatic insects from nearby bodies of water."
