Hi Gemma! I've got 3 pet sheep that are almost 11 now. My vet has prescribed Rimadyl for one of them, which is for dogs actually. I've found it quite good for her and keeps her comfortable. I also use glucosamine and No Bute from equestrian shops and Rhus Tox from my homeopathic vet. Someone I know also uses Danilon, which is bute, for their elderly sheep but obviously you would need to talk to your vet. I hope you find something that will help your oldies, as others have said you've done well to get them to that age. I'd do anything for my girls and at the moment these things I've mentioned are working, so fingers crossed for you.