My 4 blue swedish duckings are 3ish weeks old, I noticed around the 1 week mark one was smaller than the others. This morning she seems much smaller again compared to her siblings and she is mostly keeping her neck tucked in. She can stretch out if she wants to. She is behaving normally and I dont see any bullying.
I am feeding 19% chick grower with nutritional yeast, about a tablespoon per cup of food (My feed store doesnt have duck starter) and have 3 food/water set ups so everyone can eat peacefully. They also are outside eating bugs
(Shes easy to spot in the picture! 4 blue swedish and 10 rouen ducklings who are younger)
Is this a classic case of failure to thrive? Anything I can do?