10 week old formula fed bub had blueish/green poo stringy with sort of grey edges, has had a few loose b/m is this normal? also has had a few colds

Maybe: Blue stools are impossible unless you are feeding the baby something blue. If your baby is cared for at home and has no siblings it is unusual that she would have several colds. An assessment by her doctor sounds like the best plan. That way she/he can be sure she is thriving well. If you have a stool take it with you. All the best.

Probably normal: Babies poop runs a wide range of different colours and consistencies depending on their diet that are all very normal. Other events such as colds can also change things by speeding up the babies GI tract. A normal formula fed baby will have a bowel motion every 1 to 3 days, it should never be very hard or have blood or mucous in it. If you see anything concerning take a sample to your doctor for t