Thiamine (Vitamin B1) is essential for converting carbohydrates into usable energy and maintaining healthy nervous system function. It acts as a coenzyme in the metabolic pathways that break down glucose, which is the primary fuel source for your hen's brain and nervous system. Without adequate thiamine, nerve cells cannot function properly, leading to the characteristic neurological symptoms that make B1 deficiency one of the more dramatic nutritional diseases in poultry.
For backyard hens, thiamine is particularly relevant because it is destroyed by certain anti-thiamine compounds. Raw fish contains thiaminase, an enzyme that breaks down thiamine in the gut, so feeding raw fish or fish scraps regularly can induce deficiency even when the rest of the diet looks adequate. Certain molds that grow on improperly stored grain can also destroy thiamine. Bracken fern, which free-ranging chickens might encounter, contains a thiamine antagonist as well.
Thiamine is water-soluble, meaning chickens cannot store significant reserves and need a consistent daily supply. The good news is that most commercial feeds and a varied diet easily meet requirements. Problems tend to arise from specific antagonists rather than simple dietary lack.
Laying hens need about 1 to 2 mg of thiamine per kilogram of feed, which commercial feeds easily provide. Whole grains, brewer's yeast, and sunflower seeds are good natural sources. Avoid feeding raw fish regularly (cooking destroys thiaminase), and store grain properly to prevent mold growth that can destroy thiamine. If you see sudden neurological symptoms in otherwise healthy birds, thiamine deficiency from a contaminated feed source should be considered.
0.0% of daily nutrient intake
Vitamin B1 (Thiamine) makes up 0.0% of your chicken's total daily nutritional requirements by weight. That's a tiny amount — but it matters.
Stargazing posture (head thrown back over the body), loss of appetite, weight loss, weakness, incoordination progressing to paralysis, convulsions, sudden death in severe cases. Neurological signs can appear within days of thiamine depletion and are dramatic and alarming to witness.
Thiamine is water-soluble and excess is rapidly excreted in droppings. Toxicity from dietary sources is essentially impossible. Even supplemental doses many times the requirement cause no harm.
| Life Stage | Size | Min | Max | Unit | Notes |
|---|---|---|---|---|---|
| Adult | — | 1 | 2 | mg/kg feed | Water-soluble, no significant storage. Destroyed by thiaminase in raw fish and certain molds in improperly stored grain. Store feed properly. |
Source: NRC Poultry 1994; Merck Veterinary Manual
