Zuko is not quite as... Runner-y as the rest of my flock. He/she developed a big chest seemingly overnight when they were around 6 or 7 weeks old, and since then has been significantly larger and more low-slung than the rest, and never seems to stand all the way upright anyone. Is this a health issue, or is he/she possibly just not a full-time Runner? Everyone else seems to stand up tall easily and regularly.
If he/she is actiing fine otherwise, eating well, and generally just being ducky, then I would say maybe he/she's a cross. Looks to maybe have some Cayuga mixed in? Either way it's a beautiful duck!