Just finished my incubation of our own coturnix eggs. Tried 12 and 7nhatched really well. Unfortunately one died this morning

not sure why as they were all strong hatchlings and have been up and running for 3 days eating and drinking like great. Way better than any chicken chicks. Quail chicks really know how to eat and drink

perfect little quail just laying there dead. Makes no sence ;(
Will try another batch soon. This first run was from the first laying of new birds so hoping for a better fertility/ hatch rates now they've been laying for a while. From blond gals and a brown male we hot mostly blond chicks with one brown.
How long can I collect eggs for before I start to reduce the hatch rates? I only have 3 females laying daily the other one has had a few issues and laid a lot of softies until yesterday. And her first hard shell egg was pale, small and thin. Son won't be using those this they get better. Will need at least 12 to incubate so that's 4 days. I hear 5 is the max? Is that true? My chicken eggs have waited uptom2 weeks before now with a near 100% hatch rate before I started incubation.