The spacing that suits a pigeon
For a pet pigeon, bar spacing of about three-quarters of an inch to one inch is the safe working range. A pigeon is a broad-bodied, ground-leaning bird rather than a nimble climbing parrot, so the real danger is not squeezing its whole body through. The danger is a head pushed between bars after food, a neck caught while the bird twists, or a wing shoulder wedged during a startled flap. Anything wider than an inch invites that kind of probing, especially in a large flight cage built with bigger birds in mind.
Measure the actual gaps rather than trusting the label on the box. Manufacturers sometimes quote the spacing at the centre of a panel while the gap beside a door frame, feeder port, or corner join runs wider.
Why pigeons test gaps differently
Pigeons walk, shuffle, and shoulder their way around a cage floor. They peck at seed that has fallen outside the bars, they push toward a familiar person, and they may batter against the sides if something startles them at night. That steady, low, pushing pressure is different from a parrot climbing bar to bar, and it means a slightly bent bar matters. Two bars flexed apart by even a small amount can create the one wide pocket a pigeon finds.
Look also at how the bars run. Long vertical runs with wide horizontal rails can leave rectangular openings near the top of a panel. A pigeon standing on a shelf perch reaches higher than owners expect, so check the whole height of the cage, not just the floor-level section you measured first.
Checking a cage before your pigeon moves in
Run a simple gauge, such as the edge of a ruler marked at one inch, along every panel. Try it at the door edges, around the tray slot, behind food cups, and at any place where two panels are clipped together. Doors are the most common failure point because their frames sit slightly proud of the main panel and leave a crescent-shaped gap at the latch side.
Push gently on individual bars as you go. Powder-coated bars that flex under light finger pressure will flex further under a determined bird leaning and flapping. If a section springs, choose a sturdier cage rather than planning to watch that corner forever. Replace any panel with a snapped weld, since the neighbouring bars usually take extra strain and spread.
Setting the cage up once the spacing passes
A safe gap only helps if the inside layout does not funnel the pigeon into tight corners. Anything clipped through the bars should sit flush, without prising two bars apart.
Give the bird a solid-sided resting corner as well. Place the cage where household traffic passes on one side rather than all around it, which lowers startle flapping against the panels.
Living with the choice and checking again
Recheck spacing after any move, deep clean, or dropped panel. Cages travel badly, and a frame knocked slightly out of square opens one corner while closing another. Watch where droppings and scattered seed collect outside the cage, too.
If your pigeon ever gets a head through and pulls back safely, do not treat the escape as luck and leave it. Move the bird to a secure carrier, retire or repair that section, and only return the bird once every gap passes the gauge again. Keeping the cage measurements, a photo of the latch area, and repair notes together in KinsLe Family Sharing lets anyone in the household verify the same pigeon setup instead of relying on memory.