My 4months old baby

Hi mommies, Recently i sent my LO to infant care. For her 1st week LO did not poop in school but this week is LO 2nd week . Yesterday Lo teacher updat that Lo poop was watery green grey. Lo has been drinking Nan for 1 month now. Before nan lo drank similac and realised that she has not been pooping daily and LO always refused to drink it. When we change to Nan pro lo milk lo did not push the milk bottle and drink it. Lo still drink 60-80ml. Depends on my LO. LO has been pooping green since 1months plus old. I was worried because teacher post about LO pooping colour. Yesterday LO poop 4 times. First creamy green. 2nd poop is at 3.45pm and that is the picture ive attached. 3rd before i fetch my Lo and teacher told me it was green n grey.Last Lo poop is at night and it was like more of dark green i can say. Do advise me. I am so worried.