While I appreciate your concern for animal welfare, I think it is dubious with a large backfire risk to suggest this. Getting accidental benefits might be expedient in the short term (by accident) but at the risk of not making the requisite advances to get these benefits. I would see it as equivalent to guessing the correct answer to a math question. While it may be correct, you didnāt develop the tools to get there and thus are not likely to get good answers in the future.
As an example, I could imagine Givewell finding that charities that limit human births to be the most cost effective and this would backfire against you.
I think this is more sensible.