Guineas are horrible mothers, if allowed to free range they will choose to lay their eggs in hidden and unsafe places (usually out in the bushes or behind something) where the Hen and eggs usually get taken by predators. After laying 20some eggs they can and do sometimes lose interest in their clutch if disturbed, spooked, crowded by other Hens (and sometimes even for no reason at all), at any time while they are brooding. Guinea Hens in large flocks usually tend to share nests, so while one Hen has gone broody on the pile other Hens keep laying there, so not all the eggs will hatch at the same time. After the keets start hatching, the Hen brooding the nest (if she lives that long) leaves the nest and takes off with just the first few keets that hatch, leaving the other eggs to go cold and die. While out running around with the prized few keets that did hatch, she often loses the keets in the grass, gets them wet (and they die), and hawks, owls, foxes, raccoons, dogs, cat and any other predators pick them off one by one within a couple of days... and you have zero profit. NONE.
If you want to make a business out of it, here's my suggestion (speaking from personal experience here because I'm doin' it, have been doin' it, and it works, lol):
Build a huge coop and covered run, make it COMPLETELY predator proof. It's also a good idea to have fenced land and train your Guineas to stay within the fenceline when you let them out to free range too... (but that's a whole other topic there tho). Guineas are seasonal layers (Spring thru Fall), so come Springtime start your Hens' laying habits in the coop by keeping them in until they lay their eggs for the day (it's best to not even let them start the habit of laying outdoors, EVER), collect the eggs 2-3X a day, then INCUBATE them yourself in a good quality, stable incubator, raise the keets in a brooder and sell them ASAP so you have minimal cost invested. You can occasionally get lucky and have a Hen or 2 brood a clutch in the coop for you, BUT... even then they can abandon the nest or the other adult Guineas can quickly kill the keets before you collect them.