I hatched my first chicks and did a whole acclimatization thing.
https://www.backyardchickens.com/threads/a-dog-and-her-chicks.1652932/#post-28417703
We only had one mishap with a pecky little a-hole of a RIR cockerel. That little jerk was asking for it though. She didn't injure him, but cornered him and scared the crap of him.
He had pecked her several times, would jump on her back and start scratching and pecking her. I'd knock him off her and she started avoiding being around the chickens.
One day I heard a ruckus under the landing and she had him cornered and wouldn't let him by her. I wasn't outside when it happened, but I can only imagine he ticked her last nerve. He was rehomed a few days later and peace has reigned since.