It would be such a small but significant thing to pass a law requiring adding seaweed to their feed. Even if they passed the cost on, it would raise the price of meat insignificantly. It's crazy that we haven't done it yet. Same with making new roofs white to reflect light instead of absorbing it.
I looked it up and it says a 28% reduction was achieved. That's still a huge reduction and perhaps, with other feed formulations, an even bigger reduction can be made.