Chicken going bald

[firewatch]

as someof you may be aware my landlord, whos garden we share, has 4 chickens which are used as layers.
today when rounding up the usual escape suspects i noticed one had a blading patch either side of her neck.
She and one other have been scratching at there necks during the hot weather, could it be the sudden change in wether has irritated her? I am concerned incase its mites or something as i often feed them by hand titbits and as previously mentioned catch them when they escape the googlag. Any help appreciated

[tamborine]

could be mites or the cockeral often grabs hens around neck to have his wicked way.

[firewatch]

We dont have a cockeral they are all girls! Although they dont half make a din like one!