The only hen I’ve ever had go broody would only go broody in the winter. Absolutely refused to leave her nesting box. Once spring rolled around and I actually needed to set eggs she sauntered out of her box for the first time in months and a fox got her😢
There’s no real way to encourage it that I know of. They tend to do what they want and 90% percent of the time it happens when it’s least convenient to you 😅