7 Hens, 3 Days, 0 Eggs. Weather or illness?

[TxAg11]

I'm fairly new to this chicken thing, so I'm not sure when to be worries or just brush things off. Lately it has been very rainy in TX, accompanied by an increase in temperature, generally around the lower 90's. My hens have plenty of shade and often get to free range on our 1/5 acre backyard.
Before leaving on vacation last week I treated their water with Wazine-7 for a 2 day period. I tossed all the eggs for ten days prior. It has been over two weeks since then and my egg production has dropped to zero over the past 3 days. I have 7 hens, so I figure something is amiss. Are there any other medications I should give them or environmental factors I can alter to make them more likely to get back to laying? Should I be alarmed that none of my 7 have lain a single egg in the past 3 days?
Any help is much appreciated.
They're all different breeds, btw. About a year and a half old.

 

[I Love Layers]

What are they getting fed?

 

[TxAg11]

Purina Layena Pellets from Tractor Supply

 

[Wyorp Rock]

Have you checked your free range area to make sure they aren't hiding a nest somewhere, look under bushes, in the middle of plants, etc.

Any signs of respiratory illnesses - coughing, sneezing, eye/nose discharge, wheezing - Several respiratory illnesses can cause a reduction in egg production.
Anyone lethargy, not eating/drinking, puffed up, etc.?

Hot weather and/or stress could possibly cause a delay/stop laying. It's possible your leaving for vacation could have caused stress, especially if someone else was coming in to take care of them. Not saying that's what it is, but something to consider, if you had a routine that you did everyday with your girls, then make sure you put that back in place, so they know everything is normal.

Do you offer oyster shell free choice as well?

Limit treats to no more than 10% of their normal diet, offer fresh veggies/fruit.

Since you recently wormed them, you may want to add some poultry vitamins to their water and give some plain yogurt/probiotics for a few days.