Stocking red deer farming?

I have been researching red deer farming and I'm finding a lot of varying info on this subject. I have read case studies that put anywhere between 6 to 10 red deer per acre, but spoke to a farm not too far from me and he stocks 3 to an acre during summer!mer and 1 to an acre during winter. What are you guys experienced with?

Another question I'm finding it hard to get an answer to is what age is the earliest a deer can be sent to a abattoir at?

Thanks
Cole