My DD does the same hun. If she hasn't pooed in a few days the wind gets smellier and smellier 'till it's AWFUL!! Far worse than any adult smell I've had the misfortune to experience! My CHN said that breastfed babies may poo as infrequently as once a week (not sure how concerning it is if it goes on longer than a week, but may be worth chatting to your nurse). She suggested eating pears as there's a compound in them that may help get things moving for bubs. HTH