Sadly, that littlest chicky didn't make it, found it dead & cold beside the hen yesterday morning. I couldn't say for certain, but perhaps it could have survived if it had been part of the first batch to hatch and had more time to warm & strengthen under the hen before she got up to tend to the other chicks. It was the last to hatch from the second batch, and Mama was rarin' to get off that nest. But then again, it may just have not had enough of the Right Stuff to go on anyway.
I don't think I would ever try to do this again, stagger a hatch with so much time between additions. The only way it could work is if you take the first chicks away from the hen and be prepared to raise them in a brooder. You could *try* to return them to the Mama hen after the last chicks hatch, but not all hens will accept new chicks, especially week-old ones. Often it's the chicks that don't make it easy for the hen, they don't get accustomed to following her calls and act like strangers to the hen.
If I were raising rare breeds or knew I had buyers who would pay a good price for each of these chicks then I would take that time/trouble to brooder-raise the chicks I hatch. Otherwise, I prefer having a hen to tend to the chicks, they do such an excellent job and it frees me for other work.
Fifi is doing a great job with her 4 remaining chicks, it's interesting to see the difference in size with chicks just one week apart. Yes, I plan to get photos to post really soon...