Hey yall sorry i have to ask is Dark green poop normal for a 7 month old adjusted age is 4 month because she was born early?

She start with a fever 2 weeks ago we took her to the pediátric er they did all kind of test on her and they didnt find anything... 2 days later after going to the er she start it to poop green every 2 days and then until someone told me it was not normal and its been like a whole week... someone told me it may be that she has a infection or something because lately she has been really fussy.. has this happen to any of yalls baby?