You need to gain their trust first and foremost. You know you won't hurt them you need to teach them that.
You have to put yourself in their position. They have been torn away from their family and the only home they have ever known and been put somewhere strange with different noises and smells. There are also these huge giants who make loud funny noises so no wonder they are frightened.
I wouldn't handle them just yet, or if you simply must (cos they are so adorable) just gentle strokes for a minimum amount of time. The best way for any prey animal to trust you is with food. A nice juicy piece of grass, a dandelion leaf or a piece of veg. Talk to them soothingly and use different voices for different things such as poo patrol, breakfast time, veg time etc. Always talk to your piggies so they know that something is about to happen. They will soon associate what is about to happen with what voice you are using. Mine soon got the hang of "DinDins" (veg time). Talk any old rubbish they won't care! I talk to mine about what I have done/am going to do. What I bought in Sainsburys anything. Its about hearing your voice and the fact that they get used to it is what matters.
If your piggies run off don't follow them around, take things at the pace of your piggies not at your pace. Some piggies have a higher prey drive than others and will take longer to trust you. Use the piggy whispering techniques that are in the guides I gave you. Some of them may seem ridiculous but they really work!
