Hi, Michelle. I just lost my beautiful bantam buff Brahma rooster to death from terror over my dog getting out! I am ashamed to say it happened three times in four days! And, she was able to grab three different chickens, one each time. Fortunately, I was right behind her every time and within seconds of her landing on one of my babies I had her collar hauled into the air at my shoulder level. None of the chickens that were caught were injured. There was no blood or marks on them. They are fine.
But my rooster, who was never touched by the dog, was so terrified by the experience that within a couple of days I found him dead in one of the nest boxes where he had retreated. And for the record, he was on his side.
If your chickens were closely related to each other, and of a temperament like my rooster, I can imagine that multiple deaths could occur.
One of the little pullets that my dog caught had been splashed with kerosene when the dog knocked over a bucket chasing her. I had to bathe her four times. The first two times I gave her a bath, she kept fainting, she was so frightened. She would open her eyes and look around, and then pass out again. Especially when she got rinsed off. That almost sent her into a coma.
The last two times, however, she managed to get a bath without passing out. And now she is back with the others, doing fine.
I have no more Brahma roosters, but I have a couple of bantam Wyandotte cockerels that are now five months old, and I'm glad I have them. Just the other day I noticed one of them trying to be the rooster to my Brahma girls, and protect them from me. They looked at him like, "What are you doing!??" and walked around him.
I told him, "you rascal, going after the older women. "