I don't think it's anything to worry about. in the hot weather mine don't really lay good eggs but as soon as it gets cool again they are back to normal and also they layed them in the flower beds until it was cool. Good luck.
One of my chickens suddenly started laying soft shelled eggs in the summer. When the heat went away the shells were hard again. This could be similar in which case you just have to wait.
I'm quite New at keeping chickens so don't know what to feed my chickens for a treat. Any ideas about what to feed and what not to feed them would be useful. Thankyou