I have BBWs and from the size of my hens and toms I would go a bit bigger. My toms wouldn't fit through a 2x2. The hens could fit and would duck down fine, but I would still go at least 3x3. Make sure that the step up isn't going to be too high once they get big it gets pretty hard on their legs otherwise. I've found in the past that ramps for BBW have to be extremely sturdy. What I generally use is some boards of different sizes placed on top of each other to create a simple set of sturdy stairs. Even my monster boys can manage them. Hope you have fun with your turks!