EBF- poop question 😁 help

L
My 5 week old has been EBF (with supplemental pumped bottles to ensure weight gain). 
She had been having regular yellow stools consistent with breast fed babies. Past two days poop is turning greenish... And increasing a little in how often she goes...
She seems ok, still eating, happy, etc... 
Anyone else experience color change? Any insight as to what could cause the change? 
Sorry for such a gross topic! 💩