Thanks for replying! I was busy with the duckling because I was scrambling for home remedies on Google I kinda panicked.
Update i believe it has diarrhea now and still same symptoms so I'm still looking for cures. Sadly it's a lone duck so I have to make do with entertaining it with a mirror...
I'm a beginner and I believe my duckling has Riemerella anatipestifer Infection and so far the symptoms Ive seen is the head shaking, scratching head and yawning alot and also the green poop. It still seems energetic as of now but the other duckling I had whom I believe had the same infection...