The light brown leghorns are also sometimes called "Danish Brown Leghorns," and you'll notice that as adult hens when side-by-side with the welsummer, the leghorn will have a larger usually floppy comb, white ears, and longer legs with a nice big fan tail, and the welsummer will have a less rangy, more traditional european hen shape with a wider diaper-bottom and her breast feathers will have a slightly rosey hue to the more sandy brown of the leghorn's breast. But yes, at first glance the pattern is very similar.