One tip re. calf hutches. I bought a batch years ago on Ebay and I find them great as shelters for pigs up to pork weight (and occasionally, temporary accommodation for the odd smallish sow).
They're great because they are so portable, but the downside is that the pigs quickly find that out, too. What we did was to attach a wooden floor.
As someone said earlier, the hutches normally have holes for pinning them down to the ground, so we used these to fix to the wood. Makes the hutch a lot nicer and more comfortable, but also gives extra weight and stability. You can either fix permanently or add a shackle that can be undone when you need to move or clean. Look at some of the conventional arks which have removable floors. That'll give you an idea.
Good luck
Liz