Spuds will ruin your soils for other veggies for several years if you want to grow them, you are best to grow upwards (stacking old tires etc. it usually doesn't work out to be viable to grow spuds at home as you have to so a significant amount of "work" to rehabilitate the soil.

As you mentioned, it really can be up to you how big you go. Chooks will eat your veggies, so you don't want them in your active garden but they are awesome for feeding scraps and digging over gardens when you are done with them. I have seen situations where chooks are in a movable pen that is put over sections of the garden that is not being used in a cyclic rotation. The rest of the time they are free ranges outside a fenced off veggie patch

Replying from phone so will come back later to reply more.