I don't see anything in the first chapter that I would change.  Well written.  Descrïptions of characters, places, and things are all convincing.  Nice sensory input and imagery.  Dialog is handled well.  Suspense is building  (what is the connection between the two sets of twins?)  No conflict as yet, but the reader can sense it coming.

Well, there is one wee change I would make.  "Abattoir" sent me to the dictionary, and that interrupted the flow of the story.  I think "slaughterhouse" would have been a more dramatic choice.  But then, that's a matter of  differences in writing style.

Thanks. I am planning on adding more to this but at this point I am not quite sure when that will be. Summer tends to be a little hectic for writing - and I am a procrastinator anyways...

Thanks for the note on abattoir. I guess it might be more of a UK usage? Or somewhat archaic now. I will change it. At once!