In my experience this is more breed specific then the source.
A white leghorn will almost never go broody but a silkie almost always will.
I have also found that when I hatch a mixed breed batch of chickens the hens are more likely to be broody then not. Which tells me the broody gene is dominate.
I had a BO that went broody at 9 months. She wouldn't leave the nest no matter how many times I kicked her out. I finally gave in and bought a dozen fertile bantam eggs and placed them under her. She hatched out 9 of the 12. My first experience watching a broody with chicks. The care and protection she supplied was amazing. She went to war with a BA one day as the rest of the hens watched. She put an end to the aggression right there. From that day forward they all got along. John
What do you think of a white/frizzle cochin mom? Its are first time. And what do i do if she is not nice to the babys? She i in a coop with 9 leghorn pulets and a BO Cochin roo. How do you think that will be?
I am not familiar with white/frizzle Cochin girls. Just BO and BA along with OEGB's but most moms find the protection deep in their souls to protect their brood. It is amazing to watch. My BO was lowest on the totem pole and she took on the whole flock without a thought. From what I have seen most chickens respect the broody. Even the roo.
I always hatch at least one batch a year. There is something about a hen and her chicks that I just love.
I have one mixed breed bantam that simply will not tolerate my lab mix anywhere near her chicks. She goes after my dog with blind abandonment. Normally they pay no attention to each other. My dog has learned when she sees this hen with chicks she stays back.
This same hen, I have seen take on a red tail and coopers hawk. She stands her ground as her chicks hide. Last year a red tail took a dive at the chicks and then landed on the four foot chain link fence. This hen stood there and puffed up and dared this hawk to go after her chicks that were hiding in the wood pile. The hawk decided to come down to take a closer look and momma went after her with no fear. She actually flogged the hawk.
For the record, I only let momma and her chicks out of the coop when I get home at night and I can keep and eye out. These hawks around here have no fear of humans.