Eggs progressing normally at lockdown then not hatching

[brshilling]

I'm on my 5th hatch. I have digital incubator with a fan. Most of my hatches have had approx 30 eggs put in initially. I lose about 5 to infertility or a blood ring around day 10 and then the others have grown steadily to day 18 and reached the lockdown phase. Then when the babies start coming out (which has been day 19-20.. too early?) there have consistently been about 6-7 eggs that don't pip or even attempt to hatch. I've read an awful lot about humidity and temperature to be keeping it at the right levels but I'm wondering why I'm getting these results. I've used both my own fertile eggs (lavender orpingtons and lav/speckled Sussex mixes) and I tried a mixed batch of locally acquired purebreds.. welsummers,BCMs, olive eggers etc. I know BCMs are notorious for lower fertility and can be tricky but I only had 1 out of 6 that were steadily growing until lockdown actually hatch. At day 22 i can still see movement in there when I candle them but none of them have hatched out. I am trying to problem solve if my humidity is off for the type of egg or the room I have my incubator in or what. I have kept the temp at a steady 37.5 c and humidity at 55-60 until day 18 then 65-70 during 18-21. It if course spikes higher as the chicks hatch. I've seen many threads on there debating humidity levels saying the traditional 65-70 at lockdown and 60 throughout are too high. Any siggsuggest?

 

[redranger209]

I'm on my 5th hatch. I have digital incubator with a fan. Most of my hatches have had approx 30 eggs put in initially. I lose about 5 to infertility or a blood ring around day 10 and then the others have grown steadily to day 18 and reached the lockdown phase. Then when the babies start coming out (which has been day 19-20.. too early?) there have consistently been about 6-7 eggs that don't pip or even attempt to hatch. I've read an awful lot about humidity and temperature to be keeping it at the right levels but I'm wondering why I'm getting these results. I've used both my own fertile eggs (lavender orpingtons and lav/speckled Sussex mixes) and I tried a mixed batch of locally acquired purebreds.. welsummers,BCMs, olive eggers etc. I know BCMs are notorious for lower fertility and can be tricky but I only had 1 out of 6 that were steadily growing until lockdown actually hatch. At day 22 i can still see movement in there when I candle them but none of them have hatched out. I am trying to problem solve if my humidity is off for the type of egg or the room I have my incubator in or what. I have kept the temp at a steady 37.5 c and humidity at 55-60 until day 18 then 65-70 during 18-21. It if course spikes higher as the chicks hatch. I've seen many threads on there debating humidity levels saying the traditional 65-70 at lockdown and 60 throughout are too high. Any siggsuggest?

Your BCM situation is normal. I had 1 out of 7 hatch. 4 devoloped. But died. All others hatched.