We must be doing something just right because I got 6 out of 7 to hatch (my first ever) and when I thought the 7th , that I water candled on day of lock down and it showed me nothing...so I thought she was a late 'quitter' well I put 'her' in the incubator anyway...and while discarding egg carton today, I candled her again and she bobbled in the water...so...ya just never know!
I hope she hatches for you.