Rescued baby Pigeon from Crow

[Girl]

Hi,I rescued a baby pigeon from a crow attack last week Friday, the crow was on top of the baby pigeon and pulling its feathers out! I think it may have fallen out of its nest and thats how the crow got to it.
I took it to the local animal hospital and was informed that if I handed it to them, it would be pts because pigeons are considered vermin in Melbourne,Australia. I have taken care of it since. Comparing against Sarah's pics, I would estimate it at 2 1/2 - 3 weeks old.
I feed it 1 syringe full 3 times a day because it never seems hungry and always struggles when I try to feed it. After I let it wonder around and put it back into the box, thats the only time it ever chirps unhappily.
Its poo turned green Wed this week and I am alittle worried. It was only 3 days ago, Monday that I took it to the vet and was told that it looked very healthy.
Q1.Comparing it to other pigeon stories, it looks alittle slow in eating on its own and always has to be syringe fed. Is this normal at 2 1/2 - 3 weeks?
Q2. It's Friday tomorrow, should I wait till the end of this week to determine whether the green poo is serious? Is it possible that it could clear on its own? The baby pigeon is quite lively and seems happy and not acting sick.
Q3. I recently changed its feeding formula to Avione Hand Rearing Formula, could this have affected the colour of its poo?
Q4. How much should I be feeding it per day?

I appreciate any advice. Thanks.