Ive got the rancher inside a 5x5 pen with quite a few cows in it. It is powered and displaying a 5x5 grid. It is set to spawn up to 32 animals and kill after 8. It is feeding the animals np, it will milk them np, but it wont kill anything (yes there is a iron sword in there as well).

using indrev-1.13.2-BETA.jar

I can't replicate this on the current master branch. Maybe it already has been fixed?

@GabrielOlvH If this issue is still relevant, I would like to work on this.