Bearing in mind that pigs drink loads, tip it up, make a wallow from it, etc. etc. you need an easy method of transporting water.
When the pipes freeze up here I transport water in 20 litre camping bottles on the wheelbarrow. Its heavy and hard, but makes lighter work than tramping up and down with a watering can. Also if you can find enough bottles always leave a couple of full ones just outside the fence so that when you walk past (just after giving them their water) and see the upended/full of mud/piglet sitting in it water container, you will not have to walk all the way back to replenish the water.
Be prepared to get a flat stomach (well theoretically) and big muscles from pulling the wheelie full of water cans.