We have a litter of 6 pups that are 5 weeks old. We had to wean early from mom because she has a severe case of mastitis and can no longer nurse. 4 of the pups have taken to weaning great but we have two who are giving us the hardest time weaning.
The male is only skin and bones at this point, the female is around the same weight as the others but is slowly losing weight now too. We have tried everything with them but they just dont seem to want to touch the weaning food. We have been bottle feeding but even that has been hit or miss for awhile. Sometimes they eat great then by next feeding they want nothing to do with food whatsoever.
We have tried kibble mash, raw turkey mash, commercial raw cubes, even got urgent care canned food from the vet but nothing seems to be working long term, not even milk replacer. Getting real concerned about them especially the little male.

Full fat goats milk is usually a hit, try minced beef or tripe.  Try something different at every meal if they will sometimes eat and sometimes not.  May be a little early but they may prefer puppy kibble alone as it's crunchy and some like it.  What brand are you feeding?