If that bitch was mine I'd be concerned. I wouldn't expect her to be able to run or play for a long time. Maybe a pregnancy is very draining on large bitch like that. I'd ask for more pics of her in normal condition. I wouldn't want a dog that was that badly down in the pasterns. When you get your pup don't overfeed, meet it's nutritional needs, grow it slowly and do not over exercise. Sometimes that condition is environmentally caused.