We know a guy with a lovely loft of King pigeons. The variety have been selected for production and growth, pretty much the equivalent of meat rabbit breeds. I had read about them, knew about the average weight ratios from hatching to fledgling, but wow seeing them in person it hits you how BIG these birds are.
I think it was HomesteadingToday? Or maybe a backyard chicken site that discussed the amount of feed that goes into the production pigeons daily when raising their squabs. In the end, it was found to be (by the numbers anyway) better to go with smaller pigeon varieties. You'd need more birds to get the amount of meat you'd want, but you'd put less feed into the parents in order to do it.
But if you like the idea of giant pigeons, they sure are a sight to see. And you know how it is. You want to choose the animal that YOU would enjoy caring for. Good luck!