Half of baby's poos are green

[CeCeBloomer]

Reading up this suggests he is getting too much fore milk and not enough hindmilk (he is nearly three weeks old) however he gained 13 oz last week and 10 oz the week before which is great but should I be worried about the green poo? It looks a bit like algae

Green poo as the only symptom is nothing to be worried about. It doesn't even mean that there's anything wrong with the amount of "foremilk" or "hindmilk" he's getting. Both my children had episodes of green poos like this before it settled down to the typical colour.