I keep hearing people adding flax seed to a hen's diet. Although I understand that it is a good addition for omega nutrients, it is also my understanding that too much flax is actually detremental to birds. I will try and find the source that I read---it was probably a year ago, so no promises that I actually find it. I wish I remembered how much was too much (hmmmmph!)
Ok...not what I was originally looking for but here's a link to a great article about organic feeds....and a quote about flax
Flax seed, wondrously high in protein and in oil, affects egg flavor when used as more than 10% of the feed.
also ( I added bolding and italics)
http://animalscience.ucdavis.edu/avian/pfs21.htm
THE USE OF FLAXSEED AS A POULTRY FEEDSTUFF
F.H. Kratzer and Pran Vohra University of California, Avian Sciences Department, Davis, CA 95616
Flax or linseed (Linum usitatissimum L.) is grown in the northern United States and southern Canada. It is a source of linseed oil, an important drying oil for paints, varnishes and linoleum. Flaxseed may be processed by mechanical expellers or solvent extraction and the residual linseed meal is available as an animal feed ingredient. Linseed meal is an important feedstuff for cattle but its use in poultry feeds is limited.
Flaxseed contains a cyanide containing glucoside, linamarin, which releases hydrogen cyanide under acidic, moist conditions in the presence of an enzyme, linase. Under normal processing conditions involving high temperature treatment, linase is destroyed so that the subsequent release of hydrogen cyanide is not a problem.
Flaxseed contains about 34% oil which is reduced to about 5% by expeller processing or about 1% by solvent extraction (Table 1). The fiber content of the meal is relatively high, but in addition, contains mucilage, a water-dispersable polysaccharide which is extremely sticky when wet. The protein of linseed meal is somewhat deficient in lysine, and possibly, methionine. {added: methionine very important for feather growth}
Historically, linseed meal has not been a satisfactory feedstuff for poultry. It could satisfactorily replace the protein equivalent of soybean meal up to 2 or 3 percent of the diet, but higher levels caused noticeable reduction in gain and feed efficiency in broilers and poults (Ewing, 1963). The adverse effect of feeding linseed meal was greater than one would predict from the nutritional contribution to the diet and there was concern that it contained a toxic factor. At one time, it was speculated that cyanide from its cyanogenetic glucoside might be responsible for the adverse feeding value.