Serin
Crowing
Do you have electricity access near your loft?? If so, then I can offer some suggestions. I know pigeons need deep water to drink from,, They will not use nipples. Can show you what worked for me during winter.
Mine use hamster bottles, both Olive with the short bill and Skittles with a long one. So do my ringneck and diamond doves. They will definitely use nipple waterers. Pigeons and other columbids can drink by suction and will also suck water droplets off walls and floors so compared to most birds they don't need depth at all.