Maybe i've watched to much CSI, but according to my sophisticated education at the school of televised crime dramas, children/teenagers who ENJOY killing small animals and watching them die, are likely on the road to doing the same to humans. Then again, it's just as likely that they were being irresponsible with a gun and shot the chicken on accident.
Either way, i really hope they do catch whoever did it and scare the life out of them.
I'm so sorry this happened to you; i would be beside myself furious - and possibly sitting outside my chicken coop with a shotgun, waiting. But that's me.
If it comes up, and i hope it doesn't, you most certainly do have the legal right in this state to defend your home, life, and property with whatever force is necessary. I'm not encouraging you to go hunting the morons or anything; i'm just sayin'.
I'm so glad the sheriff is taking it all seriously.
And i'm so so so so sorry this happened.
And i think you handled the situation very well by calling the police immediately, etc. Way to keep your head.