Assume not. Ovalbumin and ovomucoid, the two proteins that drive most egg allergy, are very similar between hen and duck, and skin prick studies put cross-sensitisation to duck egg white at around two thirds of hen egg allergic children. That leaves a real minority who tolerate duck egg, and separately a small number of people who react to duck or goose egg while eating hen eggs happily, so the two are not perfectly interchangeable in either direction. Either way it is a question for a supervised challenge, not a home experiment.

No. A fresh duck egg grades clean for both histamine content and histamine liberation, and clean for tyramine as well, which makes it one of the more usable proteins on a low-histamine plan. The caveat is preservation rather than the egg: salted duck eggs and century eggs are cured for weeks and that ageing process is the sort that raises amines, so they should be treated as a separate food.

Effectively yes. Duck egg grades clean on FODMAPs overall and on every individual fraction we track, so no fructans, no GOS, no excess fructose, no polyols and no lactose. It also grades clean for SIBO. If a duck egg dish upsets your gut, look at what it was cooked in, since butter, cream and onion or garlic in the pan all carry loads that the egg itself does not.

Our data gives no reason to think so. Duck egg and hen egg grade the same across essentially every trigger we track: both clean on histamine, amines, salicylate, lactose, gluten, nickel and FODMAPs. The real differences are size, a richer and larger yolk, a firmer white, and a slightly different flavour. People who report doing better on duck eggs are usually reacting to the size and fat content or to an individual protein difference, not to a lower trigger load.