You should get your guinea fowl some guinea fowl friends.I used 2 x 4's on edge and flat. I think I prefer small hickory trees, now. They stay cleaner than a flat 2 x 4, are rounded while having good surface area , readily available on the property, and I like the look. Notice how dirty the 2 x 4 is by comparison, and only the guinea usually roosts on it.View attachment 1751905
View attachment 1751884
It's probably roosting on the low 2x4 because the hens won't let it roost with them on the higher branch.