Wall of text incoming explaining this totally “normal” process in the egg-industry:
Tap for spoiler
(Translated from german, source linked at the end)
Egg laying hens in conventional agriculture have a short and deprived existence. After only ten to twelve months of intensive egg production, in which they are exploited to the limits of their performance, the so-called “Mauser” follows. However, this natural resting phase, in which her body regenerates and renews the feather dress, means for the hens the end of their “usability”.
The Mauser goes hand in hand with a laying break of at least three weeks, which means an unacceptable slump for the profiteers of the animals. Instead of giving the hens this well-deserved recovery, they are mercilessly eradicated. In Switzerland, 3 million laying hens suffer this sad fate every year and are gassed or otherwise killed after only a few months of their lives to make way for young, “more capable” chickens.
(source: swiss-german animal-protection website)
Note: This is one of the reasons people (often vegans) avoid consuming eggs or products that have eggs in them.
Because it is economically not worth it processing those exhausted egg-laying hens into anything. A tiny fraction of the chickens are given a second-life through “give-away actions” by animal-welfare agencies like the one i linked but thats only for small batches since there isn’t enough demand for those millions of sub-optimal hens yearly and sadly the major selling point for the agency is that it is just cheaper to give them away than ordering the gassing-truck to put them to death. I know that the breeders are planning the spikes into the breeding process so there is enough chicken eggs to cover the market on christmas and easter, i’d guess they also weigh in factors like disease and heat waves in to manage the supply of fresh hens.