It would be nice to have a module, which can set the slaughter slider. Being able to read the chicken population could be useful too.

That can an extension of output filter for belt, but make sense to have for the setting something special.

I think it would be best to make a dedicated module for this. Putting it under any of the existing modules will not make it obvious for the user that the slider can be moved. That is unless there will be a generic "set slider" module, which I suppose could use useful for storage and both types of docks (aka all the existing buildings with sliders)

I feel the logistic modules need overhaul :-D