Eggs brittle and yolks falling apart

[Mother of Chaos]

I can confirm the irregular watering, from experience.

No one ever mentions that the irregular watering often comes from the sky and is hard to control for, other than maybe planting through X’s slashed in heavy-duty black plastic laid on the soil with drip irrigation available.

Ugh, more plastic.

 

[debid]

My first thought is an illness or heavy parasitic load. Dietary deficiency simply doesn't cause an abrupt change in egg quality. Especially in young birds. And, it doesn't sound likely given the management description. We can blame feed brands and calcium supplements but I really think this is an undiagnosed illness. Hopefully one that resolves but I would consider treating with an antiparasitic if you observe and don't see any signs of illness. Looking fluffed and a little lethargic can easily be mistaken for a reaction to cold weather when really they feel poorly for some other reason.