Possible to do the things that might encourage broodiness but if it is not in their nature then it will not happen. When I have wanted a hen to go broody, I would place many fake eggs in the nest to make it look like she has a full clutch to start incubating. Provide her with a nice safe secluded nest full of eggs and hope for the best. Try not to do anything that might stress the hen out (ie make her feel unsafe). There really isn't a way that I know of to force her into it but it might every so slightly increase your odds of it happening. Basically read how to break a hen from brooding and do the opposite .