Avian influenza H5N1 was confirmed at premises near Hawes, Richmondshire, on Thursday, 17 December.
A 3km and 10km temporary control zone and a 10km temporary movement restriction zone are in place around the premises.
The investigation is being led by the Department for Environment, Food and Rural Affairs and the Animal and Plant Health Agency.
Restrictions remain in place at two premises near Newby Wiske, Northallerton, following outbreaks earlier in December, with a 3km and 10km protection and surveillance zone centred on each site.
Full details can be found on the government's website.