Cannibalism has been a significant problem in pastured flocks since at least the very earliest writings from the agricultural faculties. It is a heritable trait, and varies widely between breeds and even between strains of the same breed. It is not restricted to laying cages, and it is not a sudden development due to more intensive raising systems.
It would be interesting if those who are involved with many different owners were to survey them about feather pulling in their flocks and toe pecking in chicks. I surveyed owners of chickens on one list and found distinct correlations between certain breeds and cannibalistic behavior. Toe pecking was more common in Mediterraneans, while one of the brown egg laying hybrids was prevalent in the bullying and terrorism category.
Today it is a significant problem in organic free range operations. I refer you to :
http://www.organicvet.co.uk/Poultryweb/disease/feath/feath1.htm
It is interesting that on this particular website feather pecking is initially attributed to "an underlying problem with the farming system" in one line, yet many of the following research papers cited indicate that more than half of flocks have cannibalism issues, and that cannibalism appears to be an inherited trait! It seems that old beliefs remain strong even though the authors are citing research that points out  clear evidence that things other than poor management or inadequate space are involved - one study even found the types of waterers used could contribute to cannibalism. One gem was the finding that ISA Browns on range were more cannibalistic than both White Leghorns and RIR/White Leghorn crosses.
~Organic/free range systems Permin and Nansen (1996) view the incidence of cannibalism, with the risk of secondary Escherichia coli infection, as a growing problem on organic farms. It is also an issue in other free range flocks. Where it is found there is usually an underlying problem with the farming system that triggers the problem (A. Bassett, pers.comm). Keeling et al, 1988 observed an outbreak of cannibalism in a free-range flock that occurred primarily in the last 8 weeks of lay. Cannibalism and pecking have also been observed in other free range flocks in England (Swarbrick, 1986). Green et al (2000) conducted an extensive postal survey of "alternative" poultry systems in the UK and showed that over 55% of respondents reported feather pecking in laying flocks.