Jullienne,thank you for your reply,no change in diet.He did take a hit from another nanny and he landed on his back.
Anke, navel was dealt with properly. Don't think copper deficiency from mum as she was given a vitamin drench.
Will look into white muscle.
Vet thought it maybe encephalomyelitis but I don't know enough about it.
Plus I don't have a lot of faith in the vet.
Thank you anke for replying!