My Dog Is In The 56th Day Of Pregnancy, Her Shoulders Were Shaking This Morning, I Put Food Out For Her And She Hasn't Touched It, Could She Be In Labour?

Possible though it's a little early but not too much. You need to start taking her temperature. When it drops to around 98 you should have pups within 24 hours and if not there is a problem or you know that's when to call the vet if it's c-section breed or going to likely be one by the visuals. That's how you know your dog is entering labor, they drop to around 98. Behaviors can vary per dog so there is protocol that tells us those things that isn't so different by dog. When they manage free whelp they are checked out in 24 hours to be sure things went okay and there are no hidden problems or they may need an injection to clean themselves out and the vet will usually go over some of the more common things to watch for coming up at that visit as well. Good luck.
http://drnelsonsveterinaryblog.com/2009/01/01/canine-labor--when-to-call-the-vet.aspx
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