Is it normal to grieve over chickens?

I'll try not to pepper this with self-pity, but no promises...

A couple of years ago, my grandpa got some chickens as pets, and we've been taking care and looking after them. That being said, we live in the country, so it's certainly not an easy task. Dogs have killed some, chickenhawks have got others, we got some more, dogs killed some, chickenhawks got others, ad infinitum. Here recently, my brother-in-law came and got one of our roosters, but he caused such a ruckus in the chicken coop, that one of the hens ran off into the woods, and it's very likely dead now. I was thinking about that, and suddenly heavy tears started pouring from my eyes, for that hen, and all the others that have died. I've just been bawling because they were killed so horrificly, hating myself for not being able to save them and for not being able to console the few still alive. I can't talk to anyone I know, because I'd get the "They're just animals" argument. My question is: Is it normal to be so heartbroken over chickens?