103 is pretty high but nmot to worry if you got it cooled down. I have a slightly lower hatch when it gets a spike like that but they still hatch.
Humidity is more important factor.
17 days to hatch for coturnix. turn off the turner/stop turning on day 14. If the incubator has been higher than 99.5 (forced air), 100.5 for still air, for a lot of the time they may hatch a day early.
I would not buy eggs from the same person you did again. I have only had one egg shipment with a high broken egg rate 20%. This one was from an
ebay guy ( imconclusive ) who knew almost nothing about his birds or eggs I found out. I have gotten two other
ebay egg buys with only 2 of 100 eggs broken so most are reputable.
There are many people on
www.thatquailplace.com who will sell coturnix or bobwhites and they all have only zero or one egg broken per 100 on delivery. Other places the do great are GQF, cutler supply and mcmurray hatchery.
I've hatched six sets of eggs one coturnix and the rest bw & ggbw.
The only real difference in incubation between the cot. and the bw is hatch dates.
The japanese quail (coturnix) start laying at about 5-6 weeks.
Sorry to hear of your woes. better luck this time