What's the Name of That Book??? discussion

Hello, I am looking for a book about the main character (female, under the age of 18) being taken in by a group of child/teen thieves/pickpockets in a city that felt like Victorian or Edwardian London (I can't recall if it was actually in London or just resembled London). The thieves are all part of a group that escaped from being experimented on by a scientist or mage (not sure which) and they all have animal features as a result of the experimentation. One boy has crow or raven feathers on his arms. They take the girl in and teach her to work with them. (view spoiler)[They need to get something from someone later in the book and the price is to let someone pluck all the boy's feathers. The book ends with them all getting on a large ship to leave the city for a while (hide spoiler)].

I read the book somewhere between 2002 and 2010. It was a paperback. It was a fairly thick chapter book, I think.

There is an "Escape from the Laboratory!" list, but I don't see it there (https://www.goodreads.com/list/show/1...)

Definitely not a graphic novel? :)

The Society of Thirteen by Gareth P. Jones? It was first published in 2013 so a long shot.

As far as I recall, the children who had been experimented on had already escaped the person who had been experimenting on them before the FMC meets them. And there was no connection to the modern day world like in The Society of Thirteen.

I found it! This is the book I was thinking of.

Snow
Tracy Lynn.
Thanks to everyone who looked :)