can a pigeon find new entry to nest?

[pijee]

My neighbours have pigeons nesting in their eaves. They closed up the hole not realizing that a mom and babies were in there. Now they have made a new entry beside the nest to keep an eye on it. The father continues to try to gain entry at the old spot, of course he is not able to now. I'm not sure if the mom is coming and going through the new entry. Would she figure it out? It is literally right beside the nest. She was scared further up the eaves when the new entry was made, but I am assuming she would go back to her babies right. There are two chicks in the mest about 4 or 5 days old based on internet pictures. Any thoughts? How long can a mom go without food or water. If she is not coming and going she has been in the eaves for two days. What about the chicks? How much do they need to be fed?