Agreed. Chicken society ain't all cute and fluffy. Often times, it can seem pretty vicious. But, as Aart says, they seem to get over it quickly.You'll learn to temper those emotions...somewhat.....as you get a better understanding about their social structure.
One thing that helped me was observing that even tho one gets what looks like(and sometimes is) a viscous peck and they run screaming bloody murder,
most times 2 seconds later they are waddling along pecking away at the ground like it's no big deal.....often right back very near where they received the peck..