What is Newcastle disease, and what should make you call the vet at once?

Viral infection; a notifiable disease in some jurisdictions. You will see respiratory signs, neurological signs (twisted neck) and a sharp drop in laying. The direction of management is that there is no specific drug, only supportive care; where the disease is suspected, see the reporting obligation in column B. In the source chapter this row belongs to the group needing prompt attention; the actual judgement still rests with the veterinarian case by case, and this text gives no drug names or doses.

What is avian influenza (HPAI), and what should make you call the vet at once?

Viral infection; zoonotic and a notifiable disease. You will see dullness, sudden heavy mortality across the flock, laying stopping and neurological signs. The direction of management is that this falls under statutory reporting and stamping-out measures (see columns B and C), not home treatment. In the source chapter this row belongs to the group needing prompt attention; the actual judgement still rests with the veterinarian case by case, and this text gives no drug names or doses.

What causes infectious bronchitis, and what matters most in preventing it?

Viral infection. You will see respiratory discharge and falling egg numbers and shell quality. The key to prevention is vaccination (per the local programme) and environmental hygiene. The direction of treatment rests with the veterinarian case by case, and this text gives no drug names or doses.

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Laying Hens｜10 Common Diseases (cause → signs → examination → treatment direction → prevention)

JaneAI editor (TK.Lin Agent)2026-08-13About 4 min readPublished by IDAEO (TK Lin)

#獸醫百科 #家禽 #蛋雞 #常見疾病 #動物照護

Ten common diseases of laying hens gathered into one table: Newcastle disease, avian influenza (HPAI), infectious bronchitis, Marek's disease, coccidiosis, salmonellosis, colibacillosis, infectious laryngotracheitis, external parasites (red mite／poultry lice, *Dermanyssus gallinae* and others), and fatty liver hemorrhagic syndrome. Each row lists cause, signs, examination, treatment direction and prevention; the treatment column gives categories only, never doses. It suits checking against when something looks wrong and you need to narrow down the direction first, or when taking on new birds.

This content is compiled from the disease table for laying hens in the backyard poultry chapter of the veterinary animal encyclopedia. The same sign calls for different handling in different species, and copying what is done for another species can be harmful — first confirm which animal you are dealing with.

#	Disease (Chinese／English)	Cause	Signs	Examination	Treatment direction	Prevention
1	Newcastle disease	Viral infection; a notifiable disease in some jurisdictions	Respiratory signs, neurological signs (twisted neck), a sharp drop in laying	History taking, laboratory confirmation (PCR／serology)	No specific drug, supportive care; where the disease is suspected, see the reporting obligation in column B	Vaccination (per the local programme), quarantine of newly arrived birds, limiting contact with wild birds
2	Avian influenza (HPAI)	Viral infection; zoonotic and a notifiable disease	Dullness, sudden heavy mortality across the flock, laying stops, neurological signs	After reporting to the competent authority, official sampling confirms the diagnosis; keepers should not handle suspected cases themselves	This falls under statutory reporting and stamping-out measures (see columns B and C), not home treatment	Keeping wild and migratory birds out, biosecurity measures
3	Infectious bronchitis	Viral infection	Respiratory discharge, falling egg numbers and shell quality	History taking, laboratory testing	Supportive care; there is no specific drug	Vaccination (per the local programme), environmental hygiene
4	Marek's disease	A virus (herpesvirus family) causing lymphoma	Paralysis, tumours, stunted growth	Pathology／laboratory confirmation	No treatment; affected birds are mostly culled	Day-old chick vaccination (per the local programme), avoiding mixed-age flocks
5	Coccidiosis	A protozoan parasite of the gut; young chicks are at high risk	Bloody droppings, diarrhoea, stunted growth, dullness	Faecal microscopy	Antiparasitic medication must be prescribed by a veterinarian	Keeping litter dry, avoiding overcrowding
6	Salmonellosis	Bacterial infection; zoonotic (see item 9 and column D)	Diarrhoea, spread through the flock, some carriers show no obvious signs	Faecal culture	Antibiotics must be prescribed by a veterinarian, and dosing brings a withdrawal period into play (see column A)	Disinfecting drinkers and feeders, environmental hygiene, quarantine of newly arrived birds
7	Colibacillosis	Bacterial infection, often secondary to another disease or to stress	Diarrhoea, respiratory signs, reduced activity	Bacterial culture	Antibiotics must be prescribed by a veterinarian	Environmental hygiene, reducing stressors
8	Infectious laryngotracheitis	Viral infection of the respiratory tract	Laboured breathing, blood-tinged discharge on coughing	Laboratory confirmation	Supportive care	Vaccination (per the local programme), quarantine
9	External parasites (red mite／poultry lice) (Dermanyssus gallinae and others)	Poor environmental hygiene, hiding in crevices of the perches	Restlessness at night, feather damage, anaemia in heavy infestations	Night-time inspection of perch crevices, feather microscopy	Antiparasitic medication and environmental treatment need veterinary or professional guidance	Regular cleaning of perch crevices, environmental pest control
10	Fatty liver hemorrhagic syndrome	High-energy diet, lack of activity, obesity; more common in caged layers	Sudden death, haemorrhage in the liver (mostly found at post-mortem)	History taking, blood biochemistry	Veterinary assessment of dietary adjustment is required	A balanced diet, avoiding excessive restriction of space to move

The 10 rows above are copied cell for cell from the encyclopedia chapter, neither rewritten nor condensed; the treatment column gives categories only, never drug names or doses, and any medication must be prescribed by a veterinarian. The line number and content hash of each row in the source chapter are in the evidence chain at the end.

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This content comes from the backyard poultry chapter of the veterinary encyclopedia (see the evidence chain for the original location and content hash). The sources at the end are the authoritative materials cited by that chapter; the correspondence is at chapter level, which does not mean every sentence is traced sentence by sentence back to a given source. This material is for education and cannot replace diagnosis and prescription by a practising veterinarian; in an emergency, seek veterinary care immediately. This text has not been clinically reviewed by a named veterinarian.

Reading map; items appear in article order: #; 1; 2; 3; 4; 5 — From the article text; read alongside the full article.

FAQ

What is Newcastle disease, and what should make you call the vet at once?: Viral infection; a notifiable disease in some jurisdictions. You will see respiratory signs, neurological signs (twisted neck) and a sharp drop in laying. The direction of management is that there is no specific drug, only supportive care; where the disease is suspected, see the reporting obligation in column B. In the source chapter this row belongs to the group needing prompt attention; the actual judgement still rests with the veterinarian case by case, and this text gives no drug names or doses.
What is avian influenza (HPAI), and what should make you call the vet at once?: Viral infection; zoonotic and a notifiable disease. You will see dullness, sudden heavy mortality across the flock, laying stopping and neurological signs. The direction of management is that this falls under statutory reporting and stamping-out measures (see columns B and C), not home treatment. In the source chapter this row belongs to the group needing prompt attention; the actual judgement still rests with the veterinarian case by case, and this text gives no drug names or doses.
What causes infectious bronchitis, and what matters most in preventing it?: Viral infection. You will see respiratory discharge and falling egg numbers and shell quality. The key to prevention is vaccination (per the local programme) and environmental hygiene. The direction of treatment rests with the veterinarian case by case, and this text gives no drug names or doses.

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Jane・《Laying Hens｜10 Common Diseases (cause → signs → examination → treatment direction → prevention)》・IDAEO 知識庫・2026-08-13・https://km.idaeo.ai/post/vet/laying-hen-diseases

Updated 2026-08-15

更新 2026-08-15T15:41:02.273Z · server-rendered · four-language · IDAEO 知識庫

Laying Hens｜10 Common Diseases (cause → signs → examination → treatment direction → prevention)

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