Ang dark green at malalat na poop ay madalas normal lang with formula, lalo na kapag may slight constipation, pero since ilang days na siya before mag-poop at nag-switch pa lang kayo ng formula, better check with your pedia just to be safe na walang issue like intolerance or something. A few of us naman noticed na kapag nag-adjust ang baby sa bagong formula, ganyan muna ang consistency for a week or two, pero kung persistent pa rin or may signs of discomfort (nakakaiyak, bloated tummy), best na ipakita sa doctor agad para peace of mind mo!