Twin XL Size Feather Bed 39 in. x 80 in. Feather beds are hard to buy in special sizes. Fine Web Stores has been lucky enough to find a small feather bed manufacturer in the United States that builds special sizes for us! Our feather beds are approximately five inches tall when fluffed up. They are generously filled with 90% feathers and 10% down. The outside cover of the feather bed, or shell is composed of a white feather proof ticking of 233 threads per square inch feather bed fabric.