Welcome, babies!
Update - it looks now like all five have hatched! Yay!
The poke turned out to be a good signal yesterday, and two babies hatched quickly after it showed. This morning, two more Bluebird babies have hatched. There is one unhatched egg in the nest, and it may or may not hatch. It can happen that eggs are unviable for a number of reasons but it is quite normal and nothing to worry about. Dr. Clara has assisted the babies coming out of the egg and also ate the egg shells for nutrition. Temperatures have fallen quite a bit, and she is warming them with her brood patch, a naked patch on her belly, and only rarely leaves the nest. Mandrake is bringing her and the babies food. They currently look like fuzzy shrimp but will change in appearance almost by the hour now.