I vote lots of sand to raise the water table there. Your chickens will have feet trouble with wet footing all the time. Is there a way to ditch the area? Then build the sand area high?. The drainage is far more important than the grass. Later' each day just pull up some hills of grass and throw it in the run. Or when you mow get the mowings in there. Vegetables are also a nice diversion. I bought a flock block the other week and boy do they love it too. The grass there would not last anyway. My 9 chickens cleared a 50x12 foot area in under 3 months. It had been grass forever and well established. In the fall give them some leaves to scratch in etc. Gloria Jean