Bad move? Egg and American cheese sandwich resulted in motionless pooping chickens

[MysteryChicken]

Almost 6 months. Both reds. They are fenced into the back yard and only accessable food is their feed and grass and whatever we give them.

No unusual behavior lately. 16 eggs yesterday, 15 today (we have 16 chickens). They were all running around goofing off till I gave them the egg and cheese.

Their poop was liquid-ish and green with a touch of white. By nightfall they were all in the coop so hopefully fine this morning.

6 Months is alittle early for a reproductive issue to crop up, but I had a hen get one at the age 1yr, which is unusually early as well. So it's not impossible.