Is it fairly common for babies to be really grumpy for several hours before they poo? My 12 week old DS was simply horrible this morning and then cheered up significantly after he filled his pants. His poo is the colour and consistency of chicken korma (nice) and pretty smelly. Is it normal to be so smelly? He farts quite a lot too and these can be smelly too. He's on Aptamil hungry baby formula and I'm thinking maybe I should switch to another brand?