Your right dullonien. Apparently the dog jumped in, the dad went to try and save it... then the two sons and daughter tried to save their dad.
Awful. Absolutely awful. God help the family.
Damn, I know how horrible it is when an animal accidentally ends up in the slurry pit. We've had a dog and a couple of cows in ours over the years. A pity the dad attempted to save the dog by jumping in himself, especially without a rope. We always rescued animals by using the back bucket of the JCB, climbing to the end and tying some rope around the animal. Unfortunately a slurry pit is very much like quick sand, very difficult to get back out after going in, and the quicker you struggle the more you're sucked under.
Dangerous things, one of many on a farm. Ours is fenced off (we used to rent a caravan on the farm years ago, and had to for health and safety), but that's not always the case. It wouldn't be unreasonable to force all farms to have some sort of safety feature next to sunken slurry pits (many newer ones are in large tanks above the ground), even if it was just a long pole or something similar.
I know how easily health and safety can be overlooked though. For years my dad's been running a JCB with no brakes whatsoever. We finally looked at it recently, and got one of the back brakes working (there's only two, one on each back wheel), but the brake lines were shot on the other side. This was obviously far from safe, and I'm sure there's plenty of situations which could have ended up in an accident, but when money is extremely tight, things like this tend to get overlooked. I wouldn't be surprised if fixing the remaining brake on the JCB would cost close to £500 (needs a new brake line, and all new braking plates, there's 6 of them).