Every year, hundreds of thousands of kittens end up in animal shelters, in need of permanent homes. But raising orphaned newborns into healthy, fluffy, frisky 2-month-olds ready to be adopted requires an enormous behind-the-scenes effort. All across the country, volunteer foster parents log many sleepless nights bottle-feeding kittens, which are even more helpless than human babies. So researchers and shelters are trying to figure out ways to make it easier.