Most breeds won't go broody, Silkies are notorious for going broody. If you want to hatch your own chicks, look into breeds that typically go broody. Even with broody breeds you could end up with one that doesn't want to brood.
I noticed my mixed breed girls had a tendency to go broody more often than a specific breed. It would most likely be in the spring when they go broody. I've had a black tailed white Japanese bantam try to brood in the middle of winter though.
You have a rooster, correct? It's important to ask, sometimes people don't even have a roo and expect fertile eggs! Do you want to deal with all of the cockerels you'd end up with? If you're willing to prossess them or have an separate all male flock than it won't be a problem. Even when cockerels are free it's hard to get rid of them, so think about how you would deal with the extra cockerels.
My last hatch was about half male, which is average. Don't just think about right now think about in a few months time when all the cockerels start to over breed your girls.
I hope you get some cute puff balls soon!