Iron deficiency anemia is nearly universal in commercially housed piglets separated from access to soil, requiring intervention that carries its own welfare implications.
Piglet iron deficiency anemia represents a welfare problem created by intensive indoor housing that removes access to natural iron sources. Preventing anemia requires painful injections that themselves cause acute welfare costs. Providing soil access eliminates both the anemia risk and the injection pain but requires housing system changes. This illustrates how housing system design creates welfare problems with cascading solutions.