First hatch complete with detailed analysis - warning long post

I have just completed my first hatch of eggs in an incubator. I am using a Little Giant incubator with automatic turner. The temperature was maintained at 99.5F and the humidity was 30-40% for the first 17 days and then raised to 55-60%. Due to a calculation error and eagerness, the eggs were removed from the turner and placed on lock down on day 17 instead of day 18.
The incubator holds 41 eggs which consisted of eggs from 2 sources. Group A included 24 eggs (Black Copper Maran and BC Maran cross) purchased for $1 per egg. Group B included 17 eggs of a barnyard mix purchased for $5 total. All eggs were loaded into the incubator within 24 hours of local purchase. I marked the Group B eggs to distinguish throughout the process.
On Day 8, I candled all eggs. For the candling, I used the work light on a bench grinder with a piece of plywood taped over the bulb’s hood with a small hole in the plywood. Based on the results, I removed 5 eggs from Group A. I candled again on Day 12 and marked 3 eggs in Group A that were suspect as not developing correctly. On Day 17 the eggs were placed in locked down (24 hrs early) and the humidity raised to 55-60%. At the time, 2 more eggs were removed from Group A and I believed 5 were likely not going to hatch. Therefore, only 12 of the original 24 eggs in Group A were expected to hatch. All 17 of the Group B eggs appeared to be developing correctly.
The first pip did not occur until Day 22; the hatch occurred over the course of days 22-24 with the following results: 12 eggs hatched, 1 piped and opened an area about the size of a dime, but then died (upon necropsy, this was not a case of shrink wrapping), 2 of the hatches died within 12 hours. 1 of the above hatches was actually an assisted hatch – after 24 hours of little to no progress, I removed the shell for 1 chick – there was some evidence of shrink wrapping. That chick will likely die tonight since it has not yet been able to stand in the 12 hours since hatching. 1 other chick has a leg that does not work correctly and may either die or be culled if conditions do not improve.
Final tally: Group A 2 of 24 eggs hatched (I believe 1 of the chicks that died after hatching was from Group A). Group B 11 of 17 hatched. I conducted a float test on the eggs that did not hatch (but were still placed in lockdown). 2 of the 15 Group A eggs floated (with 10-15% of the egg above water) while 13 sank. 6 of 6 Group B eggs floated (with 10-15% of the egg above water).
Based on the results, I concluded the following:
The incorrect lockdown start day likely resulted in some development faults.
Since the hatch did not commence until Day 22 , I will raise the temperature to 100.5F on the next batch.
Group A had a low fertility rate as indicated by 7 of 24 eggs not developing.
I am not sure if the results of the float test actually provide me any useful information.

The incubator has been cleaned and tomorrow evening I will start 41 new eggs. This time, all 41 eggs will be from my own flock and will include pure Barred Rocks with the rest barnyard mix from my Barred Rock Rooster/RI Red hens, NH Red hens, Buff hens, Golden Buff hens.
I plan to set the temperature 1 degree higher to 100.5F.
I will rotate the eggs 180 degrees twice a day.
Overall, I am disappointed in the first hatch, but I did learn a lot, my wife got much more interested in the project, and the kids learned about all aspects of the process.

 

All of the eggs were picked up. I really wanted to add some Marans to the flock, which is why I paid $1 per egg and drove over 50 miles each way to get them.

I did not crack the eggs - just a float test.

 

I did have 1 chick that went almost 24 hrs from pip to hatch and did just fine.

The only one I helped out I am convinced would have died in the shell based on his condition. As it is, I expect the chick will die regardless. Give them time - many of mine went through a long rest after pip before hatching.

 

I am using a still air incubator. I thought 99.5 was the same for both, but I will try the higher temp when I load later today. Thanks for the tip.