Incubation Egg Size: How small is too small?

[Mychickenseatmoney]

Where are you? I haven't seen 7g increments before. Here in the UK the DEFRA definitions (and what has to be followed in labelling) are at 10g intervals, from >72g = extra large, down to <43g = extra small.

The hatching eggs sent to you, ranging from 44 to 70g, cover almost the whole of that range, and that's not ideal (generally things work better if all eggs in the clutch are approximately the same size, as larger eggs/ chicks take longer to develop than smaller ones). But in principle the size differences shouldn't have any impact other than potentially stagger the hatch a day or two, and I'd expect the smallest to pip first and the largest to pip last.

The risks then attend when the hatch starts; if the incubator is opened to get the early hatchers out, it could be detrimental to the success of the late hatchers because it will transform the temperature and humidity in there. Patience is a virtue when hatching. And once they've hatched, the early hatchers have a head start over the late hatchers in everything they do, for the first week or so at least.

I'm based in the southwestern portion of the US if that helps.

Interestingly enough I've had 3 of 9 hatch. I'll take a peek later, but so far it looks like they were all on the larger end of the size range.

I'm going to let the incubator run for two additional days. Hopefully, the rest are just behind schedule.

I've had to open the incubator a couple of times, as I'm dealing with a light sussex egg that is not having a good time. I'll pray I didn't doom the rest.

All in all, I'd say things are going okayish.

I'll report back sometime midweek with final results.

Thank you to everyone's insights, it's sincerely appreciated.