It could be pregnant, lactating, or its teats could be so huge because its probably gone through multiple heat cycles without being spayed (clearly the owner is irresponsible). But it's definitely fat too. If it was just pregnant, you'd still be able to see an outline of the dog's ribs. Pregnant cats & dogs that are a healthy weight sort of look like butternut squahes - slim in the ribs, wide in the abdomen. If that dog IS pregnant, I really hope the owners get a hot fire poker up the ass. That poor dog will be whelping for HOURS, could even die from complications (because you know the irresponsible shit-head owners won't pay for veterinary intervention) Source: I'm a veterinary technician, have whelped a few litters in my day