PCGB/DEFRA LIaison Update - 12/04/2017
Poisons and Toxins
Poultry are affected by many toxins and poisons. Prevention is best as there are few antidotes available. Keeping birds away from potential toxic materials is sensible, but better still not to use anything toxic in the garden, such as slug pellets or pesticides.
Most poultry will avoid eating poisonous ones due to their bitter taste but birds are at risk from laburnum seeds, potato sprouts, black nightshade, henbane, most irises, privet, rhubarb leaves, rhododendron, oleander, yew, castor bean, sweet pea, rapeseed, corn cockle, clematis, common St. John’s Wort, meadow buttercup, vetch, ragwort and some fungi. Blue-green algae is quickly fatal, so water containers should be kept clean, especially in hot weather and access to stagnant water should be prevented
Arsenic: used in sprays for plants, rat and ant poisons and for tanalising timber, but the latter is only a problem if the timber is still wet from the treatment. Clinical signs are nervous signs and death.
Copper: either as copper sulphate or copper oxychloride fungicides. Convulsions and death follow ingestion.
Calcium: excess due to supplementation will result in kidney failure. Young birds are more susceptible than adults.
Lead: from old paint, lead shot, fishermen's lead weights (both lead weights and lead shot are no longer used on waterways, but residues are a problem). Treatable with veterinary treatment if caught early enough. Signs are green diarrhoea, muscle weakness and weight loss, confirmed by blood analysis. The head and neck may be swollen with a discharge from the eyes and nose.
Zinc: ingestion of galvanised wire, old galvanised drinkers. Signs are weight loss and leg weakness, confirmed by blood analysis. Treatment as for lead poisoning.
Mercury: used for treating grain and exposures are cumulative. Signs are weight loss and leg weakness. Residues may be present in eggs and meat for several months after exposure to the poison.
Phosphorus: found in rodent baits, matches and fireworks. This causes sudden death or progressive weakness.
Nitrates:nitrate fertilisers cause increased thirst, purple comb in chickens, convulsions and death.
Phosphides:found in rodent baits. Causes reduced appetite, coma and death.
Bicarbonates:young chicks and turkey poults are susceptible and the signs are diarrhoea, increased water consumption, death.
Sodium chloride:common salt causes poisoning in excess. Road salt can be a problem in some areas where water courses are affected. Kidney failure, convulsions and death are the result.
Potassium permanganate:still sometimes used as a disinfectant for incubators and causes sudden death if ingested.
Fungicides: these are used as seed protectants and produce depressed growth and deformities in young birds, with layers producing odd shaped, thin shelled, infertile eggs.
Herbicides: any organophosphorus ingredient is dangerous. Paraquat produces convulsions and death with geese regurgitating crop contents.
Insecticides: chlorinated hydrocarbons: aldrin (grain treatment), chlordane, dieldrin
(seed and timber protectant), DDT, lindane (only recently banned from flea powder).
All of these can cause hyperexcitability followed by death. Woodshavings from treated
wood are especially dangerous; shavings sold for livestock are from untreated wood.
Organophosphorouscompounds: diazinon, dichlorvos, malathion, parathion, dimethoate.
These are cumulative and result in regurgitation, muscle twitching and death. Can be one to
three weeks before effect.
Carbamates can kill chicks, poults and ducklings quickly.
Molluscides: metaldehyde slug bait kills poultry. Slug control in the vegetable garden may be better achieved by letting a few Call ducks free range; they are small enough not to do much damage to plants.
Rodenticides: chickens are relatively resistant to warfarin but baits based on phosphorus, arsenic or zinc phosphide are very toxic to poultry.
Phenolic compounds: are the base of many disinfectants, wood preservatives, coal tar products and creosote. The latter was traditionally used to kill red mite in henhouses but it kills young poultry and pheasants unless allowed to dry for at least three weeks before putting birds in a treated area. There are now other products more effective at killing red mite and less toxic to the birds. Drinkers or feeders should be well rinsed if phenolic disinfectants have been used.
Formaldehyde: causes conjunctivitis and respiratory distress.
Drugs: too high a dose or prolonged treatment or mixing incompatible ones will cause problems. The avermectins are useful parasiticides but are not licensed for poultry and in excess will make birds infertile or kill them. Ornamental geese seem more susceptible.
Ionophore coccidiostats (monensin, narasin and salinomycin) will kill turkeys and
guinea fowl. Always read the label on feed bags.
Furazolidone, although now banned from food producing animals, kills chickens,
turkeys and ducklings.
Sulphonamides are used to treat coccidiosis and can be toxic if the dose is exceeded
Fungal infections: Aspergillus and Candida are the main cause of disease.
Mycotoxins: aflatoxin in feed eg. groundnuts, corn, cottonseed. Crops grown in drought conditions encourage aflatoxin proliferation but most reputable feed mills test for this. Fusarium moulds occur on grains grown in cool climates. Ergots are fungus on grass and grain flowering heads. These can be prevented by obtaining feed from a reputable source and storing it in dry conditions.
Other toxins: E. coli produces bacterial endotoxins, which cause intoxication, renal or hepatic disease when toxic metabolites (products) accumulate.
Clostridium botulinum toxin (see Clostridial diseases)
Carbon monoxide: associated with the burning of fuel in an inadequate supply of oxygen.
Chick gas heaters need ventilation, regular servicing and checking. The blood of dead
chicks is bright cherry red.
Ammonia: in concentrations of 170ppm causes conjunctivitis, paralysis of the tracheal cilia (the mechanism for removing mucus from the lungs) and predisposes to more severe respiratory disease caused by a variety of respiratory pathogens. Keep litter dry and friable to avoid build up of ammonia and sufficient ventilation. If the keeper can smell ammonia it will be adversely affecting the birds.