My DS is 5.5 months now and seems to bring up fewer burps after feeding. Occasionally I'll get one out of him but sometimes there will just be nothing at all. He used to be a good and reliable burper after feeding and did quite large ones! He's 100% formula fed.
Should I be rubbing his back for longer after feeds to try and get a burp out, or is it normal for babies to burp less when they get to this age?