If the preditor was nearly as large as your lab, I don't think it was a red fox. Do you have grey foxes in the area? Or maybe wild dogs? Grey foxes aren't apt to be that brazen unless they think no one is around, which might be the case. They ARE good parents and teach their young ones well. Grey foxes can be as tall as labs since they have longer legs, and can move like both cats and dogs in stealth. Also, if it is a grey fox, they can climb trees, fences, and here they scamper up the tree, jump to my second floor balcony, climb to the top roof of the second floor and work its way back down the roofs to get to the backyard fence if the dogs are in their way. The only reason they haven't gotten a chicken is because they can't get ahold of one and get up the fence and out of the dogs reach fast enough. I'm guessing the closer it comes to winter, they'll probably step up their game a bit to get food
Hate to say it but you have this backwards. Grey foxes are itty bitty, about the size of a cat if not smaller. Red foxes are the bigger ones and come in many color phased in the wild (Red, Cross, Silver and everything in between). I once had a red fox that lacked the white tip tail and had coloring exactly that of a grey fox, on of course she was much bigger.
Hate to say it but you have this backwards. Grey foxes are itty bitty, about the size of a cat if not smaller. Red foxes are the bigger ones and come in many color phased in the wild (Red, Cross, Silver and everything in between). I once had a red fox that lacked the white tip tail and had coloring exactly that of a grey fox, on of course she was much bigger.