digitS' :
I've expressed my dismay about this list on poultryhelp.com before. The list is from a book on reptile keeping. That, in itself, is not a disqualification for information on plants toxic to chickens. Generally, a plant toxic to one animal is likely to be toxic to other animals. However, there's no explanation why some common livestock forage plants are on this list.
Probably any plant may become toxic if grown conditions like drought, flooding, over-fertilization, and such. For people who keep grazing animals, even slightly toxic forage can be bad news.
Not all that long ago I came across a
Canadian government website on toxic plants. Many of these plants are found on both sides of the border.
Once again, the folks supplying the information are trying to "cover the bases" and help farmers stay out of trouble. But, they do provide references, examples of poisonings, etc. They also provide some common sense, like these words on brassicas:
"Brassica oleracea includes common cultivated crops such as kale, broccoli, Brussels sprouts, and cabbage. All these vegetables are capable of forming toxic quantities of SMCO, a chemical that can cause hemolytic anemia in livestock. These plants also contain glucosinolates, which can cause goiter. In general, these widely used vegetables are safe for human consumption.
Cases of livestock poisoning occur when they are used almost exclusively as fodder for animals(Kingsbury 1964, Smith 1980, Cheeke and Schull 1985, Benevenga et al. 1989)."
The message is fairly clear: don't feed these plants and exclude other foods from your animals' diets.
Steve
Emphasis is all mine (bold)
When used almost exclusively means nothing or very little else, so no five lbs of cabbage for mine, and no five pounds of any brassica plant. Feeding them some as a treat should be no problem. (of which I am thankful since my broccoli is starting to head up!)