Heres something i found on the internet. Hope it helps.
Russian sage, while not being deadly poisonous, does have the potential to be toxic to people and animals. The danger is in the leaves and the flowers of the plant (which are the parts that those who think Russian sage is like a traditional sage are most likely to eat). These parts contain a chemical called thujone, which is most famously found in very small amounts in the infamous beverage absinthe. Also like absinthe, Russian sage contains a very small amount of this chemical. In large doses, or over time, this chemical may harm the liver. It may also cause hallucinogenic effects.
We have a very large russian sage in our yard, and the chickens absolutely hate it. I think it's the extremely pungent odor or maybe the slightly fuzzy leaves )r maybe it's the whitish appearance since they do tend to go after bright green leaves over other colors), but they appear to avoid it. Other plants they tend to squeeze right up against the base of to scratch and pick for bugs, but they never do this around that sage, even though it's in a bed with a lot of other plants that they often forage beneath. So I'd say you're probably alright since it's not acutely toxic (from what I've read about it) and seems to ward our off on its own.