We have plenty of hen crates, and would happily loan/sell you one, but you are more than likely miles away, so not practical. These carry 8, 10 or 12 birds so plenty big enough.
But, seeing as you only have three hens, either a cardboard box with an open top for air, but covered with chicken netting or something to prevent them escaping, or perhaps someone you know could loan you a large cat carrier which would do. New poultry crates are around £30 and second hand ones snapped up, so think these options may be the cheaper.
Just make sure you have food, and more importantly, water, to offer the hens on moving day - they do not mind travelling, but can start to wilt in a warm vehicle!!