I would expect the main effect of stronger regulation of agriculture to be the innovation signal for alternative proteins.
If passed, this would be a pretty strong carbon tax and a pretty clear signal that at least some countries will get serious about decarbonizing agriculture, so even if it leads to suffering-increasing short-term changes I would expect the long run effect for animals to be positive (essentially, it seems to me the complementarities for AP-innovation between chicken and beef seem larger than the short-term shifts one would expect -- we do not get AP beef without ever getting AP chicken).
Could be bad for animals, causing a shift from cattle and other ruminants to chickens. Chickens are killed in much greater numbers per kg of meat and I expect have worse lives on average.
EDIT: And it could increase the consumption of eggs, fish and shrimp, too.
I wouldn't just say could. I'm fairly certain this will be quite bad for animal welfare
Well, it might also reduce chicken and egg consumption, because those are also more carbon-intensive than plant-based foods. And then there could also be symbolic effects, e.g. people might come to believe that animal agriculture in general is bad for the environment, not just ruminant farming. It could also support plant-based and cultured food R&D, which could then be good for chickens.
I don't have a strong view either way. I don't think such symbolic effects matter much for the vast majority of people, and I'd guess the price effects push towards increased chicken and egg consumption. How plant-based and cultured food R&D is affected seems super speculative to me, and this doesn't seem like a reliable way to increase it anyway.
Regardless of which way my best guess would go, I wouldn't have pushed for this to happen, because I definitely wouldn't have been confident it was robustly positive for animals, and I'd guess there were more effective and reliable ways to achieve the same upsides, without the potential downsides (or similarly large ones, per unit of resources or work).