Hi,
I am trying to create a spreadsheet that tells you stocking densities depending on welfare standards (DEFRA, Red Tractor, RSPCA and Soil Association).
Could we ask the purpose of your spreadsheet out of interest?
Piglets - from new born until weaned off sow. That could be anytime from 3 weeks to 8 weeks old. Sometimes longer. Once they are no longer with the sow so their milk intake is nil they are weaners.
Again people will vary but once weaned until 14 weeks I would call them stores or growers. From 14 weeks onwards I call them finishers. I finish my pigs 20 to 24 weeks at 100 kg live weight. Commercial pigs are finished at 16/18 weeks I believe.
I'm not sure how much a cutter is referred to now but the terms were porkers, cutters then bacon pigs. Often bacon was made from a young sow who had reared a litter.
We would have pork joints, sausages and bacon from our finished pigs. Cull sows would be sausage and bacon but with a lot more trim and more fat on the bacon.
Absolutely echo HappyHippy's comments on climate, soils, indoor, outdoor units.
It is also possible to finish Saddlebacks within two weeks of a modern breed such as a Large White.