well it sounds like you need to brood the rest of them yourself. Not all hens are good moms.
Lots of information on this site on how to do it. Mainly, keep them warm and dry, away from the others and good chick feed starter.
If you've got an incubator to put the rest of the eggs in, I would do so. Otherwise, you can keep a close eye on them and take them away as they hatch. If someone will be able to keep an eye on it, you could take the eggs and put them in a box under a warm light with a thermometer to monitor temperature, and hatch the rest that way, I've had to do that before when I had eggs hatching under a hen and the other chickens were pecking at them and eating the chicks as they hatched.