green poop

hi everyone i got two girl hairless rats from a pet store the other day because they had bad allergies in the eyes and i didnt think they were taking care of it. they had the girls on hard hay like stuff and they are HAIRLESS not good for skin or allergy.. any way they are doing sooo much better with the eyes but one of the girls always poops on me when i pick her up and her poop is green? i am new to rats but i have not seen that before. anyone know what that is about? ps. they are so sweet, both are pink eyed. thanks trish