I know you want a serious answer. But it is true, it's the one that will sit. Sometimes you have to wait and see. You want a very protective hen that will peck and bit at your hand when you check the eggs under her. I've had silkies, black australops, and banty crosses sit. The banty was the best. She had to be tough in my neighborhood. She needs a nest away from the others and by herself. She won't eat or drink while she's setting. So, I use to feed her chicken grain soaked in water. When she would peck at me, I would put a spoonful of wet grain in front of her and she would peck that instead. Surprise! She'd gooble down the food. I didn't feed her lots, just enough to sustain her. She needed the water, too. She will poop while sitting and I would have to clean that out. That was fine. It kept the eggs and nest clean.
A good setter will sit for the 3 weeks and then take excellent care of her chicks. 5 or 6 six eggs is a good number for first round. They may not all hatch and make it, but she has to take care of them and teach them things and protect them..
Banties are feisty and determined. Silkies will set but are wimpier chickens.