While I haven't found any transformations at the moment per say, I have found two series airing in January 2017 that have a strong potential for featuring transformations. Interestingly both are about young witches attending school.
The first is Little Witch Academia, which started as a short film in 2013, is getting an anime series in January. The trailer does feature a bird transforming into a witch, so there is further potential within the series itself. the two trailers are below:
https://www.youtube.com/watch?v=S3jFdqs4jUQ
https://www.youtube.com/watch?v=pgz2bMz-Zz8
The second is a new series of 'The Worst Witch' based on the books by Jill Murphy and produced by CBBC in the UK. The book series and it's previous TV Movie and CITV series have both featured prominent Pig and Frog transformations and it looks like the new series may feature them as well.
I can't find any trailers for this series, just a short preview of the first episode. So instead I'll leave you with a clip from the original series where Mildred Hubble transforms a young Jyn Erso into a pig:
https://www.youtube.com/watch?v=E9ZxNbGVUlw