It depends on how long the hen has been off of the nest. If the eggs were fertile they should have developing chicks inside. I have had eggs abandoned for a couple of hours and I tucked them under other broodies and had a good hatch rate. I'm not proud of this but once I had a hen who had dud after dud egg under her and I didn't want her to continue to sit on her eggs if they weren't going to hatch because they were about three days past due so I threw the eggs away in the garbage and forgot about them. A few hours later I walked into my kitchen to get a glass of water and I heard "Pew! Pew! Pew!" coming from my garbage can. I found the peeping egg (and recandled the rest to make sure!), put it in my incubator, and named the chick "Oscar" when he hatched.