Princess of Thorns by Stacey Jay (Delacorte hardcover, 9 December 2014).
Dearest (The Woodcutter Sisters # 3)Hew by Alethea Kontis (HMH hardcover, 3 February 2015).
I serendipitously happened to pick up two books based on the swan fairytales one right after the other.
I had remembered the story as The Seven Swans, possibly from Grimm, but a search on the Google brought up a Grimm tale called The Six Swans, as well as one by Hans Christian Andersen called The Wild Swans.
Both have a similar theme: the brothers are cursed to be swans and can only be released from the curse if their sister weaves them each a shirt of nettles, not speaking until the task is done.
Of the two, Dearest sticks more closely to the older tales. The protagonist of this story is Friday Woodcutter, whose talent is sewing. After her sister Saturday conjures up an ocean (see Hero, Woodcutter Sisters #2), Friday ends up at her sister Sunday's (see Enchanted, Woodcutter Sisters # 1) palace.
Friday notices a young kitchen-maid frolicking with swans on the shore. When her squire Conrad tells her that the swans nest up in the tallest tower of the palace, Friday climbs the many stairs and finds seven young men sleeping on the floor. When she learns that the mute kitchen-maid Rampion is their sister and is trying to save them from a curse, she immediately does what she can to help.
In Princess of Thorns we first meet Aurora, daughter of the Sleeping Beauty. After losing her mother at the age of seven, Aurora is raised by Fey relatives. But when her brother Jor is captured by the ogre queen who has taken over Aurora's kingdom, now 17-year-old princess disguises herself as a boy and sets out to rescue him.
Along the way, she joins forces with Prince Niklaas, who must marry a princess before his 18th birthday to avoid the fate of his ten older brothers. Niklaas promises "Ror" that he will help "him" raise an army to rescue his "sister" if Ror will convince her to marry him. Because both characters are hiding things from each other, this plot is somewhat more complex.
Both books are well-written and compelling. Both mingle multiple tales and have a suitably evil villain. Both left me wanting more, though Jay's book gives no indication that there might be a sequel.
FTC Full Disclosure: I borrowed these books from my local library.