I would collect all the stray marked eggs, it being early in the incubation, and try to secure the broody nest better. If you simply cannot secure the nest so the other hens can't disturb the eggs, perhaps you need to hang it up for this go-round and give yourself time to get better prepared to handle a broody sitting egg for 21 days.
Once incubation gets well underway, this sort of shenanigans will kill developing embryos, making the entire effort moot.
Once incubation gets well underway, this sort of shenanigans will kill developing embryos, making the entire effort moot.