Help!? ALL my chickens acting weird????

[CountryFlock]

My chickens have their wings down and not how a normal chicken would have. They are breathing heavily with their beaks open. It is a normal day. It is 80F. They are very nervous. They are making some vibrating sound. We introduced rice to them a couple days ago and we fed them that like a few hours ago??? Please help

 

[Eggcessive]

Was the rice cooked? That probably wouldn't hurt them, but I would stick to just 16-20% chicken feed, and never feed them uncooked rice. When chickens are hot they breath open-beaked and hold wings away from their bodies. Are they out in the sun, and how hot is their coop? Is the vibrating sound comin g from their throats?