honestly, raccoons (and all predators) like to get a meal with as little work as possible. If the hen was near the fence, he would have grabbed her easily. If a noise or light scared him, then he would have just took off with what he had. He could have also merely been "taste testing".
the problem is that now the coon knows where a quick and tasty dinner can be found.
Meat-eating squirrels aren't very common. Usually limited to when they are starving. My great-grandparents have owned chickens since 1900 (yes, he was born in 1892) and have NEVER had a squirrel eat a chicken. He did say that he had found them nibbling on dead birds before, but those were scrap pieces after butchering. A squirrel might kill a small chick or break some eggs, but they aren't rampaging through your yard with an eye to bite the heads off of chickens.