toxic means thta if that is all they are eating and in large amounts it can cause problems... usually due to build up of certain minerals in liver or kidnesy, OR by not allowing absorbtion of neccessary minerals etc.; same as humans....
too much dark green leaves and you prevent absorbtion of calcium in your diet due to oxalic acid; etc. ; toxic and poison are two different things.
toxicity is measured by amounts needed: for sheep and goats there are certain weeds that they can eat in xmall amounts but if eaten in large amounts they develop anemia (certain plant/weed in israel that these animals luuuv to eat); i killed 9 male ibex many many years ago by being good hearted and giving them cut forage of a certain tree. little did i know (and neither did the zoos in teh area) that this tree in certain seasons has huge amounts of nitric acid stored in the leaves and that affects ONLY the males of the ibex for some reason taht i dont remember now. in additon, someone had fertilized (withnitric acid) their orchards and the run off had been absorbed in the graze/forage area of the ibexes. i came to give grain one morning and 9 animals laid dead. post mortems/vets/zoos etc - now we know.
cherry leaves and frut are the same; almonds are also, and yet, we here inisrael eat green almonds (with the green furry skin before they are hardened) from both sweet and bitter almnd trees (prussic acid)..
howver, oleander leaves are poisonous. their toxin kills instantly and in minute amounts even for a child or a goat kid. (had that happen one year also, somene gave us forage with a few leaves apparently in the forage , of oleander. one goat didnt notice, ate the leaf and died.)
cabbage has the same affect as does spinach: they cause absorbtion problems in mammals.
goats and camels eat olive tree leaves that other mammals wont touch as the leaves are slightly toxic and very bitter.
avocado and parsley can kill parakeets however. but chickens luuuuuuv tomatoes.
