Actually it's normal/natural for Guineas Hens to go broody after laying anywhere between 20-30 eggs... or they may even go broody sooner on a big, shared nest because the size of the pile also stimulates broodiness. No forcing needed, as long as the Hen (or Hens) are comfortable with the laying spot being private enough and they are undisturbed.Your hens may not start setting for months. They don't do it automatically just because they are laying eggs. If you want a hatch sooner you will have to start incubating them inside and don't count on your hens. They don't go broody until they are ready, and there is no way to force them. I'd pick up the eggs and start over inside if I were you.