2 hens dead in 2 days no sign of injury or illness

[JLS]

Two days ago I found a 2 year old hen dead. Rigor mortis had not yet set in. There were no signs of injury or illness. She died laying on her stomach with her legs straight out behind her, as if she had just fallen forward while standing. I have had chickens for 11 years. I have never found one dead in this position. Fast forward two days, just now I found a second hen dead (same breed - buff orpington - and date of birth) in the same position. It has not been exceedingly hot the past few days. The only things that are new/different is a 'flock block' and table scraps which included various lettuces, leftover pork spare ribs, bread. All of the food scraps were fresh, no mold. No mites or lice are present. Both birds were vibrant, robust, and lively just hours before they died. The flock is housed in a large converted shed and have a huge fenced run. They do not free-range due to heavy predation risk.

Any thoughts about possible causes of death? I have absolutely no idea why this is happening.
I have 8 remaining hens - same age - Buff Orpington, Easter Eggers, Polish.

 

[Wyorp Rock]

I'm very sorry for your loss.

The only way to know what's happened would be to have a necropsy.
If you still have the body, sending it to your state lab would give you a lot of information. Alternatively, you could perform an informal one yourself to see if you can tell.
https://www.metzerfarms.com/PoultryLabs.cfm