Are either hen broody now?
If not just pull the eggs and store them in cool place 60ish until they go broody. I would load the nest with fake eggs and change them when they are broody. Leaving them there is a good way to get rotten eggs...
And then I am doing it myself right now too,,SO Do as I say not as I do... I have not been getting any Minnesota Australorp eggs for almost a week. I have a small "coop" off that run and I mean small. Holm saw it he can tell you how small. The other day I thought to myself... " self, do you think she could be laying eggs in that old nest/coop?"
I checked and she had a half a dozen eggs in there. So I decided to let her keep laying there. I expect her to go broody any day now. Because she is an Australorp she will most likely go hard broody. So ignore what I said...lol
I had a chicken stashing eggs In a haybale, there were about 8 of them by the time I found the nest. I don't think that because they go off and lay somewhere else means they will go broody, it just means they found a better nest box and no one is collecting eggs.