So sorry to hear you have a badger, just when the hogs have returned. Very sad that one of the hogs was carried away. I can imagine how distressing that must have been.
I’m sorry but the only thing you can do to help the hedgehogs is stop feeding them. It’s very likely that the badger will be back and if you keep feeding the hogs, it will just be a feeding station for the badger. Usually when hogs know there is a badger around, they’ll keep a low profile and probably move further afield, but you don’t want to encourage them back by providing food. Almost any feeding box/structure you provide would be unlikely to keep a badger out – they are very strong, are used to using their claws to get through wood, for insects, digging, etc. and, as Simbo 65 says, the hogs could easily be caught on their way to and from any feeding station.
There is a very small chance that the badger is a displaced one who is just passing through. For instance, if you are in a culling area, a badger may have been displaced from it’s sett and be looking for a new place to live. In that case you might be able to consider feeding the hogs again eventually, but not until a suitable length of time has passed. You would need to carefully monitor for signs of the badger. Also, if you can, ask your neighbours (keeping the necessary social distancing, of course) whether they have seen or heard of badgers in the area. If there are a lot of badgers around, it would seem more likely that they have moved into the area. But also if you see a badger on more than one occasion it is more likely it is staying in the area. In which case, it isn’t safe to feed the hogs. The badger is clearly not averse to catching hedgehogs.
Sorry there isn’t really an easier solution.