Eggs can get accidentally squished if the hen is a large breed (like an 8 lb brahma) and has too many under her without enough bedding to cushion things. Since some of my urban flock have proven to be stubborn broodies (namely my bantam wyandotte and cochin/d'uccle mix), I also enjoy watching them hatch out eggs the natural way. It was extremely cute one day when I caught the Wyandotte 'talking' to her eggs (sticking her head under herself and clucking) when it was getting near hatch day.
a hen can really squish the eggs? I had one broody hen lay on them all the way.. it's not like we should prevent her from having a "stretch-leggy" i let mine do that and she comes back and warms them up... if she didn't come back in half hour to an hour i'd go out and see what happened to her.
Wait, how are incubator chicks happier? I would think a chick is happy when they can peak out of their momma's wing. with incubation they don't have their real momma around, it's sad.
True that with natural way, there's less eggs she can handle to hatch than an incubator. But with an incubator, esp a turner machine, you need many eggs to hatch to get this benefit.. then you get so many birds to feed at a time.