Very loose droppings!

13 May 2019
I have a 27 year old retired mare and for the last three weeks have been gradually strip grazing her on to rather lush grass - about 1 foot a day. She has been fine until this last weekend, when her droppings have become very loose - almost cow pat like. I have now stopped giving her the new grass and am giving her hay as well in the field (she lives out 24/7 except for coming in twice a day for a bit of TLC and rug change).

She isn't doing any more than usual, just loose. This hasn't happened in previous years and I wonder if I should worry or just wait for her to acclimatise to the fresh grass.

Thank you all for any advice.