First, congratulations on sale of ewe lamb!

Griffinwood is on the way!
Second, sorry about the attack on the lambs. This is serious that you had a successful attack with the Anatolians on guard. Not only a money loss on the dead wether, but also heartbreak for Dominic.

Not to mention money expense in vet bills. This is why we all try to keep antibiotics on hand for emergencies.
From my experience with coyote and dog attacks (we have had quite a few over the years), the 4 puncture wounds on the wether's neck are likely from one kill bite. Upper and lower fangs make 4 punctures, 2 on either side of the neck. Shaking could account for a broken neck. The injury to the rear leg could be from the opening attack as the predator (dog or coyote) tried to grab the rear leg while chasing the lamb. Did Hera (or Leonidas) have any bite marks on them? Probably bite wounds on their faces since the Anatolians would have come at predators from the front. (Rika has scars on her face from a tussle with coyotes who came in after lambs. They managed to kill a lamb but were not able to drag it off or eat it before Rika arrived. They were starving after the fires, and fought to try to keep the carcass instead of running away.)
Finding the injured lamb next to Hera is normal behavior for an LGD. Having her come to meet you and then return to the injured lamb is also correct behavior. The Anatolian will not leave the side of an injured (or lambing) animal other than to greet you or seek assistance from you. Excellent protective behavior by Hera.
It is too bad that your game cameras were not working since there are several possibilities here for what happened:
Scenario 1. Outside predators. Several dogs or coyotes got in and attacked the 2 lambs. The wether was killed quickly so Hera did not get to them in time. Hera was able to drive off the attacker(s) who went on to attack the ewe lamb. After driving the attackers from the ewe lamb, Hera then stayed close to the injured lamb to protect her from another attack. In this scenario, since they were able to attack a second lamb after killing the first, there were probably at least 2 attackers. During the attack Leonidas broke through the fencing to assist Hera in driving off the predators. These dogs are powerful enough to do that if they see a need such as a predator attacking the flock. Our old Pyrenees broke through a fence to try to save one of our Dachshunds who kept getting out of the yard and was carried off by coyotes.
Scenario 2. Leonidas. If Leonidas is the culprit, he must have been able to access the pasture. Maybe he chased both lambs in an attempt to play with them. He killed the wether quickly (possibly accidently) then started chasing the ewe who was spooked by the attack and started running. That would account for the numerous injures she sustained on her legs and sides. Hera did not attack him in time to save the wether lamb. Since he is part of her pack and has been allowed to be with the sheep, she may not have realized what he was doing until it was too late. When he went after the ewe lamb she stopped him from killing that lamb.
Since the lambs are used to the guardian dogs, they are less likely to run from dogs or coyotes that
sneak up on them. If it
was Leonidas, the sheep might let him walk up to them without running away. They know him and don't equate him with danger. They will run from other predators,
but if the attacker doesn't spook the sheep, and can get close enough without detection from the LGD, they will be able to attack the sheep before the guardian can reach them. Since the wether showed no signs of being eaten, Hera must have driven them off before they had a chance to start eating. If it was neighborhood stray dogs, they would just pull down the animals without eating them. In that case you would expect to see more damage to the wether's legs and sides if they were chasing him andbiting at him. This is why I think he may have been killed first, before much chasing began.
About the lamb's injuries. She should heal up fine since you have antibiotics for her. Do you have any mastitis tubes? They are excellent for puncture wounds which have a tendency to heal over on the outside while building up infection inside. Using mastitis tubes for punctures is an off-label use but effective. If you don't have any (they are now only available with prescriptions) see if your vet will give you a prescription for some and keep them in the fridge for use on punctures. Another way to disinfect punctures is using a syringe filled with iodine or hydrogen peroxide to wash them out. The mastitis tubes are an antibiotic.
Hope you can figure out what happened. Hopefully it was Scenario 1, not 2.
