This gets into a deep philosophical question people spend too much time arguing about. In short, some would argue suffering is multiplied by the number of sentient beings that experience it, others would argue only the average "amount" of suffering matters. You can end with some absurd paradoxes if you take either to their extremes.
The reality is probably somewhere in the middle.
> In short, some would argue suffering is multiplied by the number of sentient beings that experience it
Factored by how cute the animal is. As a producer of plants for human consumption, it's quite obvious that orders of magnitude more animals are harmed in that process than are ever harmed in traditional meat production. But they're mostly ugly insects, so nobody cares.
> The reality is probably somewhere in the middle.
I think such paradoxes demonstrate we probably need a completely different approach than anything we've done so far.
Utilitarianism feels to me like Mill & Bentham discovered basic arithmetic and didn't even realise there was more to maths than that.