I have found a lot of threads on Iowa Blues and they are pretty consistent. The information is almost identical to what is on page 1 of this thread.
This is from raising-chickens.org
Iowa Blue Facts:
Size: Male: 7 Ibs. Female: 6 Ibs.
Comb, Wattles & Earlobes: They have medium to moderately large single combs with six well-defined points that stand upright. Their wattles and earlobes are medium to moderately large as well, and they are all bright red.
Color: The beak is horn and the eyes are dark brown. The shanks and toes are slate. In spite of the name, the bird does not hold to true blue coloring. The head is silvery white and the neck and upper breasts have white feathers with a slender black stripe down the middle transitioning to black feathers with white lacing. The lower breast, body, legs, wings and tailare bluish black to gray with penciling. Male: The back and saddle are similar to neck. Female:The back is bluish to gray with penciling.
So if we go with that discription, the brown birchen hens would be too brown. The brown Birchen roosters can be overloaded as well - I even have one with a duckwing pattern.