Broody Hen Response to Weather Change

[centrarchid]

I have three hens in the latter stages of incubation. Latest to set is a good 12 days into cycle. Over last few days it has been warm (90's), windy with very low humidity. Durinig the last few days clutches were totally covered. Very early this morning a front brought a lot of humidity but temperatures were still elevated (mid 70's). All three hens were setting with a fair number of eggs exposed. Now, later in day all hens are covering clutches again. Anyone ever see such behavior?

 

[they'reHISchickens]

We have 5 hens setting at the moment. I will try to keep an eye on that and report. Last summer we had a hatching is superhot weather and lockdown by the hen didn't exist. She spent half her time OFF the nest or partially on. I assumed she knew what she was doing and it certainly was hot enough to hatch on their own