The latest was on December 5 near Thirsk - the seventh case near the town since November.
There was also an outbreak at a farm at Ravensworth, near Richmond, on December 3 and one at another site near Thirsk on December 2.
In November there were five confirmed outbreaks near Thirsk, mostly at commercial poultry farms, and two near Leeming Bar.
Exclusion zones preventing the movement of birds have been set up around the affected farms.
In all cases the H5N1 strain of avian flu has been detected.
Housing measures have been in place for parts of North Yorkshire since November 21 following a number of confirmed and suspect cases of H5N1 avian influenza in poultry in the area.
Public health advice remains that the risk to human health from the virus is very low and food standards bodies advise that avian influenzas pose a very low food safety risk for UK consumers. Do not touch or pick up any dead or sick birds.There is no impact on the consumption of properly cooked poultry products including eggs.
The additional biosecurity regulations mean that in addition to housing all poultry and captive birds, keepers must continue taking extra precautions to keep their flocks safe. This includes regularly cleaning and disinfecting equipment, clothing and vehicles when entering or exiting sites and limiting access to non-essential workers or visitors.