16 week hen passed away! Why?

[MysteryChicken]

How so?
The medication in medicated feed is amprollium, a thiamine (B1) inhibitor, B1 is essential for the the bodies use of food for energy, the nervous systems health and brain function and muscle development.
Medicated feed is usually only used the first few weeks then switched to non-medicated to avoid stunted birds.

There's not enough Amprolium in the feed to do any real harm. It's a preventative dose for chicks, not a full on treatment dose.

Plus, the dose is so low it won't do anything for a young pullet, nor an older hen.