>>58637105https://serebii.net/legendsz-a/pokemonsize.shtmlAccording to Serebii, the "XS" size corresponds to a size value of 0-15 out of 255. 16 values out of 256 total possible values equals a 1 in 16 chance, or 6.25%. If that's true, the odds of me not hitting that 6.25% chance a single time after over 400 catches are so astronomically small that it's a statistical anomaly. I'm literally more likely to win powerball than I am to end up with no XS Pokemon after 400 catches.