Right, I meant individual (potential) animals existing in the future.

I don't think suicide is a good indicator here because we could imagine an evil scientist designing a mind that will constantly experience the worst feeling ever but that still wants to continue to go on living. Is it wrong to not prevent such a mind from being turned on? I strongly think so. Also note that evolution might function a bit like the evil scientist in the hypothetical, because evolution is all about optimizing gene-copying success and not about the well-being of individuals.

I think most people would agree that some forms of existence are worse than not being born, especially if they imagine the torture as vividly as they can. (I think someone linked to footage from factory farms somewhere in this comment section.) An interesting question is whether there is a duty to procreate, assuming that beings will live lives that overall go well. I don't think factory farms qualify for that, even if we set the bar pretty low, but if they did, the evaluation would come down to population ethics, where things get messy because it has been proved formally that no possible solution fulfills some seemingly very conservative adequacy conditions.