The Northern Fowl Mite’s entire life cycle is spent on the host where it feeds on blood and is a source of irritation to the bird. Eggs are laid in masses at the base of the feathers, usually in the vent area.
The eight-legged adult Northern Fowl Mite is about 1/26 inch long and dark red to black. There are four stages in the mite lifecycle: egg, larva, nymph, and adult. The complete lifecycle from egg to egg-laying female can be as little as five to seven days. This can result in rapid increases in mite populations, especially on layers and breeders kept for extended periods.
Adult female mites complete the egg-laying process in two days after taking a blood meal from their host; the number of eggs laid per female is relatively small – usually two to five. However, the short lifecycle means that mite populations can rise rapidly, with newly infested birds capable of supporting a mite population in excess of 20,000 per bird in nine to ten weeks under favourable conditions (source: Williams, 2010). Mites tend to congregate near the vent area, but the back is also a popular site as the mite population increases, (see Figures 1, 2 & 3). Severe infestations can remove as much as 6% of the blood volume of a hen per day.
Northern Fowl Mites are not as hardy as Red Mites and generally die within three to four days without a host. Mites are easily transmitted from bird to bird by direct contact or by crawling from one bird to another.