UPDATE - 9:23PM: Okay, so Trooper seems to have made a full recovery after his nap. I think he was cold and in shock from landing in the water bucket. He doesn't appear to have any broken bones, but he is definitely a juvenile. Just took him outside with full intentions of letting him go, but he can't fly at all, which explains how he ended up in the bucket. Problem is, if I leave him out there now for his parents to find him, he will surely get eaten by raccoons. He is probably hungry, but I just can't stand the thought of leaving him out there as bait... I did hand-raise two baby cockatiels, but I am definitely not a pigeon expert, haha. I am going to try and get hold of one of the local wildlife centers to see what they recommend.
UPDATE - 6:59AM: Brought Trooper outside this morning; he did great overnight and even ate some bread. I was initially just going to put him in the chicken coop for his parents to find him, but he up and flew to the top of the barn to meet his family on his own and then took off with the flock! Guess he just needed a bit more rest :)