when i hatch coturnix i run incubator at 99.5 with 20-30% no more then 40% humidity until last 4 days then i run humidity in 80-85 % range i average 75% -85% hatch rates i run auto tunners. hope this helps i have had 100% hatch twice on my own eggs, shipped eggs i hatch anywhere between 45 and 50%. i incubate 120 eggs at a time.
most of my quail hatch at 17 days but it also depends on age of eggs when they are started for incubatation process if you have eggs older then 7 days they can take longer to hatch so if you are like me and wait until you have good batch to hatch you will want to give some of the older eggs extra time. as far as what you have quoted never have heard that and i have been around poultry since i was 4 yrs old and now approaching 43. my dad and i used to hatch in old sears incubator that used light bulb for heat. we would always give extra few days. just incase we did something wrong during incubation period. i am at 5700 ft elevation never even took that into consideration to tell you the truth i have always kept my humidity lower until last 4 days and then get it up high. if you have it to high during incubation i have seen issue with feet and legs be weak and deformed in chicks. i know my dad used to go no water until last 4 days of cycle. he believed that to much humidity cause to many legs issues (where i get it from). he's raised birds all my life i didnt start doing anything with them until i was around 4-5 yrs old. i hatched out lots of coturnix in my life, not to mention chickens and pheasents we use to hatch out 3000 ringnecks a year for our farm in southern idaho. only i do different is quail and pheasent i have temp at 99.5 and chickens i bump it to 100.5. use this if you want hopefully it works for you works for me. some might disagree with me and that is fine, not saying my way is the perfect way but it works for me.
one thing i also want to say is i usually pull my chicks after couple hours and put then in brooder
congrats on the success
