No need to worry as long as the color of the stool is not black, red or brown. Greenish or yellowish poo poo is healthy. Doctors also say baby having poo poo from many times in one day to once every five days are still considered normal. Even if they are a bit hard like clay, as long as the babies are not in pain while stretching, there is not much we can do but to massage their tummy to ease the process.
My son only has stool once every 2-3 days. His stool is sometimes sticky as clay and sometimes soft like paste. Color may also change between green and yellow. I was also very stressed and worried before but doctors say they are normal.