This is another hybrid hen, and she looks a lot like our cuckoo marens, so I’m guessing the marans is the ‘mar’ in marsbar. I’m only able to tell her from the marens in our flock by the spiky hairdo.
The ‘bar’ bit of her name is probably from a hen called a cream legbar because the Marsbar lays beautiful blue eggs, just like the legbar.
She’s a friendly, inquisitive bird and her eggs are so pretty. I always make sure there is one in every box I sell.