I had something similar happen to me the last week in April. With 27 chickens going from 12 eggs one day and then anywhere from 0 to 3 eggs a day for a month. I did take and move them from roaming 1 acre, no feed, to an area of 38 feet by 100 feet and a new chicken manson 10x20. 5 bagsof feed a month. Then they started laying again. I did feed them 48oz of yogurt mixed with dry feed, middle of May. Temps where in the 80's. Last week I went from DuMor layer crumble to Purina layer crumble and the egg production, 3 days later, went up to 12~14 a day then 17, 9, 18, 19, and 16 today. The temp this last 2 weeks has been high 90's to over 100. June egg count was 304, Mays was 151, yogurt and over 2 weeks of daily highs of 100 plus.
The only major difference in the feed is some vitamins.
Not sure if this information will help but that is what I did.
I'm have 6 EE all 2 years old, 2 RR 3years, 2 Barbed Rocks 2 1/2yo. 9 RR and 4 black Australorps and 4 barred rocks 9 months.