Putting Golf balls in there nesting box will increase the chances of them going broody and a quiet relaxing environment is know to increase broodiness.
As you have already received some great advice, I will just wish you good luck.
I hope you enjoy being a BYC member. There are lots of friendly and very helpful folks here so not only is it overflowing with useful information it is also a great place to make friends and have some fun. Unlike non chicken loving friends, family and colleagues, BYC’ers never tire of stories or pictures that feature our feathered and non feathered friends