There are ways to mitigate unintended side effects. Start with a small small number of farms, AB test with no seaweed, small amounts of seaweed, medium amounts of seaweed, large amounts of seaweed, also AB test on which Farmers know which sample they are getting, iterate next year on results with larger number of Farmers. Buy insurance to compensate Farmers if the seaweed kills them. Discover why they died. Iterate with solution (if possible) or cancel (if seaweed always results in eventual death). Continue to keep large population of seaweed free cattle to mitigate possibly of extinction via unexpected long term consequences of seaweed.