Maybe the next question to be asked will be whether pellets lead to boredom and feather-pecking, as is often claimed, but that's one for the future - until then I firmly believe it's an old wives' tale!
I believe it, but it doesn't apply to all pellets, or all chooks, and in my opinion, the pellet form itself is not at fault, it's the lack of nutrition in the pellet when combined with the breeds which are prone to cannibalism, which is itself blameable on the husbandry methods utilized in keeping and developing these breeds, and also the method used for selecting breeders: production statistics alone. Harmful social traits were not taken into consideration when selecting breeders. The financial bottom line was all that mattered, which is really a false economy when we're talking about health, lol....
Some pellets i.e. most commercial layer pellets (and mashes as well) were specifically developed in conjunction with some breeds, i.e. those designed for high production, short lives, very restricted and refined diets, to live in commercial factory settings.
These hens have very carefully restricted fat, oil and protein levels in the feeds because when they get enough to meet their own needs as well as the physical demands of their production, they lay less, build up body fat, and are more likely to go into moult or brood. The commercial bottom line prefers hens who lay nonstop until culling age, and to ensure that, they have to be kept nutritionally desperate.
Processing feeds into pellet or mash form cooks the oils and fats they need in raw form for total health. Just like us, they do better with raw oils etc rather than cooked ones in their diet, and not meeting their needs causes a kind of generationally escalating insanity, or 'pika' specifically, because the starting health status of each chick is dependent on and visibly impacted by the preceding few generations beyond its immediate parents. Over thousands of generations of being raised exclusively on this specifically limiting diet, bred for greater and greater production in overcrowded environments, cannibalism and neurotic behaviors developed and became strong breed traits because under these circumstances they rendered benefits and were positive traits. In the wild they'd die out almost instantly.
These chickens have been inadvertently selected for cannibalistic traits and neuroses, before the concept of culling for negative social traits took hold as good husbandry practice, because before that, all they did was remove the corpses, debeak them, etc. As a rule, each hen was selected for breeding based sometimes solely on her output. If her output was slightly greater because she cannibalized her cage-mates, she would pass on the behavioral trait that was helping her to both secure her nutritional needs, produce slightly more, and thereby a place in the breeding program.
Her cage mates contain raw oils and proteins and fats, which are converted easily and with little waste compared to cooked proteins, fats, oils etc, which allow short term survival but tend to become stored fat deposits and waste products unlike raw alternatives.
Many of these 'complete' commercial feeds cause diseases of malnutrition. Some of those diseases take years to kill so it's not a commercial concern unless you're trying to market the very healthiest eggs possible. Every hen who cannibalized would be a bit more vital in health terms than her non-cannibal sisters who subsisted on cooked pellets or mash alone. Her chicks would hatch healthier by a slight margin and therefore perform better than other chicks of which some are already suffering diseases of malnutrition by the time they hatch, which is obviously due to the mothers' lack, which in turn is due to the grandmothers' lack.
There are high producers who don't cannibalize, of course, but there's more than one means to an end. It's no coincidence the cannibalistic/neurotic traits are confined to mainly a few massively commercial breeds and any breeds raised in the same environment, on an identical or similar diet, for enough generations.
I've personally experimented for years with breeding in and out various traits, behavioral, taught, etc, and so have many scientists, and it's proven to take only a few generations to breed a behavioral trait in or out, such as cannibalism, and it only takes one intense experience in an animal's life to cement a certain reaction to a certain stimuli into its descendants.
Some hatchery chicks will begin cannibalizing others as they hatch, before they've even used up the absorbed yolk supply. It's now just how they think, this perception of one another as walking food sources.
Cannibalism isn't something all chooks automatically resort to when needing more nutrition, or bored, or seeing blood, despite the common belief; it's an aberrant behavior we bred into some of them.
Best wishes.
