Old MacDonald wouldn't recognize today's egg-layer factories, where male chicks are destroyed at birth and the others de-beaked, and sometimes de-toed, in preparation for the wire mesh cages where they will produce small, pale, watery eggs for a year and a half before being made into soup. (Under natural conditions, layers can last for 15 to 20 years.) With boars, it is the penis that is cut off--or surgically rerouted--to prevent their beating the superior artificial-insemination sperm to sows in heat. Most pitiful are the milk-fed veal calves, forever reaching for an object to suck (nipples on their feed buckets would be hard to keep sterile), and licking any available nailhead because the pale, anemic flesh desired by gourmets calls for an iron-deficient diet. For those unmoved by the plight of confined, crowded, genetically manipulated animals, Mason and Singer point to the string of feed additives, some carcinogenic, that end up in our meat, to the high saturated fat-to-nutrient ratio in factory-fed meat, and to the waste of resources involved in producing these heavy animals. By the authors' calculations, about a third of the fossil energy that goes into the operation is returned in food energy; and from 4 percent (in beef) to 23 percent (eggs) of the feed protein is converted to animal protein. Taxpayers are reminded of the money spent on government purchase of artificially priced milk, on advertising (USDA ""consumer education""), and on University research. (Square pigs and featherless chickens are now on the boards.) Farmers are unhappy with their mechanized lifestyle, long hours, and binding debt to the new, big-time company stores. And with high animal-fat diets discredited, consumers should be ready to make the modest diet changes and demands (strong labeling laws, prohibition of questionable additives, an end to public subsidies that prop up factory farming) that Mason and Singer suggest in closing. Their hard-hitting report is meant to arouse indignation, and it will--among an audience Singer didn't reach in his sober, ethics-oriented Animal Liberation.