The avian flu pandemic started in early 2022. I looked up old news articles and a lot of them are dated February 2022. It really did increase egg prices.
The collusion quotes in this article start in October 2022, though it doesn't say exactly when the collusion started.
As far as I can tell, avian flu did create a supply shock, which did raise prices. When the avian flu problem started going away, the egg companies started colluding to try to keep the egg prices high.
According to one lawsuit, Cal-Maine wasn't impacted at all by the avian flu, they just jacked prices up 270% anyway while using the avian flu as an excuse.
> Meanwhile, in context and during the class period, egg producers like Cal-Maine increased egg prices by as much as 270% in 2023 despite having zero Avian Flu outbreaks in their egg laying hen layers on Cal-Maine affiliated farms (https://www.classaction.org/news/antitrust-lawsuit-says-prod...)
On its face, this is a normal market response: if demand is unchanged and overall supply goes down, prices go up.
The criminal conspiracy part here was manipulating the index prices in tandem so that everybody raised prices in lockstep.
> if demand is unchanged and overall supply goes down, prices go up.
How much did supply go down considering that Cal-Maine Foods, Inc is (or at least was) the single largest supplier of eggs in the country? Ultimately their profits increased 718% (https://www.cnn.com/2023/03/29/business/egg-profits-cal-main...) which seems unlikely to be explained away by reduced supply. There were price gouging and fixing prices with the other large suppliers to prevent consumers from moving to fair-priced eggs of competitors.