Species
Chicken: adverse event reports
1,073 reports, 0.1% of FDA's animal drug adverse event database
1,073 adverse event reports in FDA's database concern chickens: 0.1% of all reports received from January 1987 to March 2026. 29 arrived in the 12 months to March 2026, close to the 29 of the 12 months before. That is 0% of all reports received in those 12 months and about 27 reports a year over the whole record.
By active ingredient, the drugs named most often are narasin + nicarbazin (24.8% of chicken reports), monensin (17.8% of chicken reports), narasin (15.3% of chicken reports) and oxytetracycline hydrochloride (13.1% of chicken reports). Drugs given to the most animals lead the list for that reason; brands are masked in the public data.
The terms listed most often are death (38%), lack of efficacy (protozoa) - Coccidia (20.9%) and lack of efficacy - NOS (9.8%). 58.2% of reports stating seriousness were classed as serious (38.6% across all species), and 52.4% record a death or euthanasia (6.4% overall).
FDA posts reports quarterly with a delay of three to six months, so the newest months are incomplete and usually grow in later releases.
Drugs named most often, by active ingredient
| Active ingredients recorded for the drug | Reports | Share of chicken reports | Share of the drug's reports that concern chickens |
|---|---|---|---|
| Narasin + Nicarbazin | 266 | 24.8% | 85.5% |
| Monensin | 191 | 17.8% | 4% |
| Narasin | 164 | 15.3% | 37.9% |
| Oxytetracycline Hydrochloride | 141 | 13.1% | 32.6% |
| Tylosin | 61 | 5.7% | 5.2% |
| Zoalene | 42 | 3.9% | 93.3% |
| Avilamycin | 33 | 3.1% | 57.9% |
| Hygromycin B | 27 | 2.5% | 79.4% |
| Nicarbazin | 21 | 2% | 67.7% |
| Bacitracin | 20 | 1.9% | 4.8% |
| Tylosin Tartrate | 20 | 1.9% | 3.9% |
| Amprolium | 16 | 1.5% | 4.1% |
| Enrofloxacin | 9 | 0.8% | 0.1% |
| Lasalocid sodium | 9 | 0.8% | 3.6% |
| Tylosin Phosphate | 9 | 0.8% | 4% |
| Sulfamethazine | 7 | 0.7% | 6.4% |
| Sulfadimethoxine | 5 | 0.5% | 0.3% |
| Albendazole | 4 | 0.4% | 0.5% |
| Decoquinate | 4 | 0.4% | 2.5% |
| Deslorelin Acetate | 4 | 0.4% | 1% |
| Diclazuril | 4 | 0.4% | 2.4% |
| Fenbendazole | 4 | 0.4% | 0.1% |
| Tiamulin | 4 | 0.4% | 3.1% |
| Ceftiofur Sodium | 3 | 0.3% | 0.2% |
| Ivermectin | 3 | 0.3% | 0% |
| Lasalocid | 3 | 0.3% | 2.3% |
| Roxarsone | 3 | 0.3% | 18.8% |
| Tetracycline | 3 | 0.3% | 8.6% |
| Butorphanol Tartrate | 2 | 0.2% | 0% |
| Carprofen | 2 | 0.2% | 0% |
Ordered by report count, which follows how widely a drug is used. FDA states that these data "cannot be used to estimate the risk associated with the product or compare one drug or device product with another". openFDA masks brand and manufacturer names in adverse event records, so the reports counted here cannot be attributed to a particular brand.
Signs listed in reports
share of chicken reports listing the termall species
- Death38%408
- Lack of efficacy (protozoa) - Coccidia[the product did not have the expected effect: coccidia]20.9%224
- Lack of efficacy - NOS[the product did not have the expected effect]9.8%105
- Increased mortality rate8.8%94
- No sign[no clinical sign was reported]7.5%80
- Accidental exposure[exposure that was not intended]7%75
- Lack of efficacy (bacteria) - NOS[the product did not have the expected effect: target not specified]5.9%63
- Loss of egg quantity5.2%56
- Residues in eggs4.8%52
- Enteritis3.8%41
- Recumbency[lying down and unable or unwilling to rise]3.7%40
- Anorexia[not eating]3.4%36
- Death by euthanasia[the animal was euthanized]3.2%34
- NT - Abnormal necropsy finding NOS[NOS: not otherwise specified]3.1%33
- Digestive tract disorder NOS[digestive problem, type not specified]2.5%27
- IGA Animal mortality greater than expected2.5%27
- IGA Animal morbidity greater than expected2.3%25
- Dermatitis[inflamed skin]2%21
- Dehydration1.9%20
- Lameness1.9%20
- Ataxia[unsteady, uncoordinated movement]1.8%19
- Diarrhoea[diarrhea]1.8%19
- Ineffective, coccidia[legacy FDA term: the product did not have the expected effect (coccidia)]1.8%19
- Depression[dull, quiet or withdrawn]1.6%17
- Found dead1.6%17
- Loss of egg quality1.6%17
- Death-slaughtered1.5%16
- Lethargy[unusually tired or inactive]1.4%15
- Ineffective, antibiotic[legacy FDA term: the product did not have the expected effect (antibiotic)]1.3%14
Single ingredients, pooled across combinations
- Narasin401 reports · 37.4%
- Nicarbazin284 reports · 26.5%
- Monensin192 reports · 17.9%
- Oxytetracycline Hydrochloride141 reports · 13.1%
- Tylosin61 reports · 5.7%
- Zoalene42 reports · 3.9%
- Avilamycin33 reports · 3.1%
- Hygromycin B27 reports · 2.5%
- Bacitracin21 reports · 2%
- Tylosin Tartrate20 reports · 1.9%
- Amprolium16 reports · 1.5%
- Lasalocid sodium10 reports · 0.9%
- Tylosin Phosphate10 reports · 0.9%
- Enrofloxacin9 reports · 0.8%
- Sulfamethazine7 reports · 0.7%
- Ivermectin5 reports · 0.5%
Age and weight
Age of the animal
Weight of the animal
Outcomes and report types
Outcome recorded in the report
What kind of report it was
Coloured bar: chicken reports. Grey bar: all 1,357,245 reports. Outcomes are as stated by the reporter.
Trend
Reports by month FDA received them. The newest months are incomplete because FDA posts reports with a delay of three to six months.
| Measure | Chicken | All reports |
|---|---|---|
| Reports | 1,073 | 1,357,245 |
| Classed serious, of reports stating it | 58.2% | 38.6% |
| Death or euthanasia recorded, per 1,000 reports | 523.8 | 63.8 |
| Filed as lack of expected effectiveness (wholly or partly) | 23.2% | 23% |
Questions about chicken reports
How many adverse event reports involve chickens?
1,073 reports through March 2026, 0.1% of the database; 29 in the latest 12 months.
Which drugs are reported most often for chickens?
By active ingredient: narasin + nicarbazin (266), monensin (191), narasin (164), oxytetracycline hydrochloride (141) and tylosin (61). The order tracks how widely each is used; brands are masked in the public data.
What signs are reported most in chickens?
death (38%), lack of efficacy (protozoa) - Coccidia (20.9%), lack of efficacy - NOS (9.8%), increased mortality rate (8.8%) and no sign (7.5%).
What ages are the chickens in these reports?
under 1 year (52%), 1 to 3 years (7.4%) and 4 to 7 years (0.6%); age is not given in 40% of reports.
Do more reports mean more risk for this species?
No. Counts follow how many animals are treated and how readily their owners and veterinarians report. FDA states that "there is no certainty that the reported drug or device caused the adverse event" and that the event "may have been related to an underlying disease, other drugs used at the same time or other non-drug related sources."
How do I report a problem?
Call the drug company using the number on the label, or send Form FDA 1932a to FDA. See the guide on how to report.
Where this comes from. Counts are built from the openFDA Animal & Veterinary adverse event bulk files released 28 Sep 2026, which hold reports FDA's Center for Veterinary Medicine received through 31 Mar 2026. openFDA masks brand and manufacturer names in these files, so drugs are counted by the active ingredients each record discloses and no figure is attributed to a brand, application or company. Ingredient names, and the separate reference lists of approved products, follow the FDA Green Book as of 30 Sep 2026. No report text, lot numbers or reporter details are published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.