Well, you have plenty of room! Temp/weather should not be an issue. Dogs - not an issue if they are afraid of them, and are not harassing them, besides they are probably quite used to them anyway. At 2, the heritage breeds (like Wyandotte) should still be laying ok.
Do you think they are molting? When was their last molt?
Also, are they acting lethargic or different (ok, the roosting is different)?
Wondering about mites. Have you checked their vent areas and under wings for parasites, like avian lice or the base of their feathers near the vent for mites and mite eggs? The mite eggs look like heavy dust clustered around the base of the feather shafts. Scaly leg mites will cause the scales on their legs to "fluff" up - look different.
Check their feet for bumble foot. It is a bacterial infection - often you will see a black dot or "plug" at the point of infection on the bottom of their feet. You can google "bumblefoot" to see pics.
Lastly, are they eating a drinking normally? A normal amount of feed?