Poultry health questions: mite infestation and Virkon instructions

Answered by poultry vet Victoria Roberts BVSc MRCVS

Q) My hen hut seems to get mite infestation at different times of year. Someone said the mites were only a problem in the warmer weather. Is this true?

A) Victoria says: Unfortunately, red mite and Northern Fowl mite (NFM) are not seasonal, they just breed more quickly when the weather is warmer. They thus become a problem faster, red mite sucking the blood of the hens at night and NFM doing the same but, as these are on the birds all the time, the damage is quicker. In warm weather it takes just seven days from mite egg to breeding adult. Both types of mite can survive for months without a meal. Beware secondhand hen huts as these may well have some very hungry red mite in which will take a meal off a person in desperation. Red mite are spread by wild birds and NFM tends to be bought in, so please check all new stock by looking under the tail for the tell-tale signs of dirty feathers and moving mites. Diatom (DM) is effective in the hen hut and nestbox and can be put on the birds as well, especially on the NFM.

Q) Please could you confirm the dilution of Virkon for footbaths and general disinfection? I found the label on the sachet very confusing.

A) Victoria says: I agree that it is not clear since in one sentence it talks about 1:100 dilution for general use i.e. 5g of powder in 500ml, this is 1% concentration. Then it talks about other concentrations without explaining them. If the disinfectant is needed for Aspergillus clearance, the concentration must be 3% (15g in 500ml) and for all disinfection, a minimum of 10 minutes is needed for efficient use. Footbaths can be 1% and the liquid is effective for 14 days, depending on the amount of muck present. I use 3% when cleaning my incubators but need to remember that more than 30 minutes immersion is harmful to metal. Gloves should be worn when using the disinfectant to prevent skin reaction and do not breathe the powder! Product sizes are sachets of 50g, a tub of 5g tablets, or up to a bucket of powder of 5kg.