Battery cage chinchilla and foxes in fur farming, and most recently for the Asian palm civet for kopi luwak production of coffee. An early reference to battery cages appears in Milton Arndt's 1931 book, "Battery Brooding", where he reports that his cage flock was healthier and had higher egg production than his conventional flock. At this early date, battery cages already had the sloped floor that allowed eggs to roll to the front of the cage, where they were easily collected by the farmer and out of the hens' reach. Arndt also mentions the use of conveyor belts under the cages to
What Hurts the Most hip-swiveling chorus after a flurry of robotic drum beats is certainly a good giggle." Kurt Kirton of About.com named it one of the album's standout tracks. Chuck Taylor of "Billboard" gave "What Hurts the Most" a positive review, writing that "this track is remixed into a frothy uptempo anthem, complete with requisite percussive thump and an exulted vocal (with 12 mixes in all) that leaves the lyric's potential heartbreak in the dust." Taylor ended his review, asking "Wouldn't it be wondrous if American programmers renewed their vow in 2008 to put variety on the airwaves—or do we really need a