Young diamond dove won't stand eat drink or perch!!!

[Sir Sacabambaspis]

I came home from school to find one of my diamond doves was on the floor and it wasn't looking very good. I check it and it's eyes were slightly closed and it won't stand up. I checked it's crop and it was empty which was wierd because I filled all the feeders yesterday and it was eating fine. And there was still plenty of food left. What is happening to it is it sick or did it possibly hit is head flying around the cage?

Here's a few pictures

 

[Sir Sacabambaspis]

I also started to hand feed it seed and it would eat if I put the seeds in it's beak and it even started to drink a little when I gently dipped the tip of it's beak in the water.

 

[Sir Sacabambaspis]

I ended up dieing after I brought it inside. Rest in peace buddy you were loved.