I have had three strains of Delawares here. Our summers start in May. Daytime temps rise to over 100 F, sometimes as high as 120 F. It doesn't cool down until Oct. Nature does my selection for me, in this regard. Two of the strains of Delawares fared well. One line started dropping dead as soon as the heat set in. Only a few survived. This demonstrated to me how it's the strain, not the breed, that determines heat tolerance.
My single combed Silver Dorkings do very well in this heat. I may lose one elderly bird each year. So yes, you can have Dorkings in the heat.
There are many chicken & egg farmers in this region. All have production breeds. All experience huge losses due to the heat. When the temps spike suddenly, they often lose the entire flock. Another example of the importance of having birds selected for your environment.
In addition, the birds who do best here, regardless of breed, seem to have the sense to seek out shade or water. It's usual to see my flock standing under the sprinklers or in the water pans.
I am so glad to hear that Silver Dorkings do well in this heat since it gets pretty hot here in southern AZ as well, and this really is the breed I'm favoring right now. I may have to pick your brain in the future about breeders I may be able to purchase some chicks from.
