Here is one study that looked a specific facet of the relationship between fermented poultry feeds and toxins.
"CONCLUSION
Fermented whey added to poultry feed acted as a biopreservative, improving its resistance to fungal contamination and increasing its shelf life."
http://onlinelibrary.wiley.com/doi/10.1002/jsfa.6669/abstract
"CONCLUSION
Fermented whey added to poultry feed acted as a biopreservative, improving its resistance to fungal contamination and increasing its shelf life."
http://onlinelibrary.wiley.com/doi/10.1002/jsfa.6669/abstract