LOL, oh sure, real clear, right up until that moment one of your damn pigeons crapped on my glasses!
Your balloon-pigeon analogy, like all analogies are only an image of reality, and at some point breaks down into meaninglessness. Take for instance the presumption(?) that all the matter expanded at the same rate from the moment of the BB (i.e., all matter was on the surface of the balloon). To use your balloon analogy, I would expect the balloon to have and infinite number of concentric inner layers, all having some amount of the matter on each of those balloon surfaces.
--Boot Hill
Well, sure. But parts of it serve as aids to mental visualization of how observations in an expanding universe will nessecarily differ from those in a "flat", non-expanding one.
Take for instance the presumption(?) that all the matter expanded at the same rate from the moment of the BB (i.e., all matter was on the surface of the balloon).
That's not an assumption, that's a given. I'm sorry if I wasn't clear enough (and perhaps there's some confusion caused by cross-over concepts with the earlier "raisin loaf" example, is not directly comparable).
A curved 2D universe would be like the surface (and *only* the surface) of the balloon. Any points inside or outside the surface of the balloon itself wouldn't even be *in* the universe as anything observable by inhabitants of that 2D universe. They and all the contents of their universe would exist and interact *only* within the curved surface of the balloon.
Similarly, although our 3D universe has curvature, it's through a direction/dimension that is beyond the constraints of our own 3D existence. All objects and all expansion takes place entirely within our 3D realm. In the balloon analogy, all objects are on the surface of the balloon, any moving object (including photons) travels along/around the surface of the balloon, and can not "shortcut" through the air-filled area in the middle. If they could, they would be seen vanishing from the "ballooniverse" and then suddenly reappearing elsewhere after an inferred "faster than light" travel through a wormhole (since light itself in the "ballooniverse" is constrained to traveling along the curving surface of the balloon.
To use your balloon analogy, I would expect the balloon to have and infinite number of concentric inner layers, all having some amount of the matter on each of those balloon surfaces.
This is not the "raisin bread" example. As the balloon expands, all points and objects on its surface expand outward with that surface. None are "left behind" inside the balloon, and none were inside the balloon to start with even when the balloon was not so much inflated.
For that matter, the same issues apply to a flat rubber sheet that is being stretched outward in all directions, which helps avoid the distraction of the "inside" of the balloon, but a balloon being blown up is more familiar and easier to visualize.