I did it in 2005, as long as the old loft is easily accessible its easy. Pair them up in the new loft, only let one sex out at a time. When they return to the old loft get them in and take them straight back, do it a few times and one or two will start to learn the new loft position. After a while they will all learn. NEVER feed them in their old loft though as their new home should be the only place they can get food. I raced mine on widowhood and they would fly two and frow between the lofts and were fitter for it, and I got some good combine positions with them to. Not that I condone violence, but I was told a story of someone settling a loft full of pigeons in a day by simply taking them to a new loft and when they returned to the old loft scaring the hell out of them, not sure exactly how though!!