Hi! Haven't tried Birch Tree personally pero a few of us tried different full cream brands during mix feeding at ang common experience is ang poop consistency really depends sa individual toddler, some kids adjust agad, others take a week or two to settle. Best approach is to transition gradually, mixing it with what your baby's used to first, para hindi ma-shock ang system niya. Keep an eye on kung may constipation or loose stools, tapos adjust pacing based sa what you observe sa diapers niya, every toddler's different talaga!