Some might, some might not. You can keep track of the ones that do go broody, and keep them as long as they stay in good health.Thank you for your answer.
Will the mixed chickens keep the broodiness though?
For laying hens, you will usually not want to keep them for very many years, because each year they lay fewer eggs than the year before. But a broody hen can usually keep raising chicks every year for many more years than that. So the broody hens do not need replacing as often as the egg layers. That means you don't need to raise or buy as many replacements for the broody hens as you would for the egg layers.