The really hot weather *can* effect the eggs before being laid causing them to be runnier.
Storing on the counter for two weeks... is very likely your issue. I would start storing in the fridge if possible... it makes a HUGE difference and we even eat eggs that are 6+ months old and STILL better than store bought.
When stored on the counter, for longer periods of time than say a week I have noticed thinner whites, easier to pop yolks and even weakened shells. None are an issue when stored pointy end down in the fridge. Sure eggs look beautiful on the counter. But even cool enough for a sweater is not the same as a constant 38 degrees of most fridges. Our house is so cool... I turn the heater UP to 58-60 in the winter. Store them long enough at room temp and the opposite happens... evaporation makes everything thick and gooey and sticking to the inside of the shell.
But the older the ladies the lower the haugh unit. 2 isn't that old yet.
I wish folks new the truth about egg storage and the impact it has on
quality! When I was a kid they taught us that eggs stored at room temp AGE 7 times faster than those at fridge temp. While I'm not sure of the accuracy as to ratio... I am 100% sure that it is a fact.
I would LOVE to see you do an experiment with your new eggs and store some from the same day in the fridge and on the counter for maybe a week and then do a side by side comparison! But make it even more intriguing and do some for 2 weeks also!
I PROMISE... it makes a HUGE difference, according to my experience not hear say. And truly believe it can go a long way to keeping your patrons content.
ETA: one more egg quality issue link...
https://www.backyardchickens.com/articles/common-egg-quality-problems.65923/