You might be doing everything you can for Freya and her kits. Hand rearing newborn rabbits is very challenging. If the kits are too weak to latch, you might try consulting a vet for further advice.
The two bales of hay might be from different parts of the field or processed differently, leading to variability in quality. Try using a different part of the second bale or mixing it with another bale to see if it makes a difference. Hay quality can vary even within the same batch due to...