question about guinea poop..

[birdbrain5]

i have my guineas penned up for quite some time now so i dont have to egg hunt, even tho they have been super stingey with the eggs! this is thier first year. i noticed today when cleaning up they have REALLY gross poops in thier run, real dark green and smelly

more smelly than usual. it was runny also. i never noticed this before. nothing has changed for them, not real recently anyway. i changed my birds over to layer pellets instead of mash, but this was over a week ago. they have been eating plenty. any ideas why this is? they seem and look fine. i did get eggs out of the girls today and yesterday, so thats a good sign i think...