It has been confirmed by the December issue of Shueisha's Bessatsu Margaret magazine
that Ookami Shoujo to Kuro Ouji
will get an OVA to bundle in volume 12 of the manga, to be released on April 24, 2015. The OVA includes a popular chapter that will not be adapted in the TV series
, which is currently airing.
Source: Scan via ANN
Ookami Shoujo to Kuro Ouji OVA