Even if someone's dog is ok with THEIR chickens (or toddlers, or cats, or rabbits....fill in the blank), it doesn't mean it'll be ok with everyone else's......there are also so many other things:
-dogs don't know their own strength, and can totally accidentally hurt things
-sometimes they just try to play and play too rough
-lack of communication between different species can lead to violence
I'm so sorry about the loss of your chickie

Hopefully *** will take the dog away soon. It's good that broody came out relatively okay.