Do you know how old the rats are? Felix looks like a rat with renal failure. I have had quite a few rats who started looking like that around 18 months old and they get progressively worse but can still run around and be happy for several months. They get a sucked-in waist, you can feel their ribs but often if they had a bit of a belly then that stays for quite a while. I will take pics of my oldies later to show you for comparison. If it is renal failure, my vet suggests cutting out animal-based protein from the diet. As for his skin, it looks like he has buck grease (orange spots) which is normal, especially in older rats if they don't groom properly. With the spots, my best guess would be protein sores, from a diet too high in protein. A lot of people just feed the rats sunflower seeds and dog biscuits, both of which are high in protein. A normal healthy diet should sort him out if that's the case. Some studies have shown that you shouldn't mix medicine with natural remedies because some natural ingredients (like rooibos) can affect how the antibiotics work. So I would suggest only using one or the other. Or at least doing the natural remedies in the morning and antibiotics in the evening (or vice versa).
Keep up the good work and I hope these guys flesh out soon.
Owned by: Niffler, Grindylow, Snidget, Bertie Bott, Drooble Gum, Pepper Imp, Sugar Quill, Fizzing Whizzbee, Lumos and Nox.
Love you always: Timothy, Butterscotch, Nutmeg, Arwen, Eowyn, Gryffen, Pegasus, Hazel, Macadamia, Indigo, Bear, Milo, Cocoa, Nesquik, Rosie, Valancy, Stirling, Chocolate, Trufflehunter, Reepicheep, Puzzle, Jewel, Poggin, Fledge, Mr Tumnus, Numair, Polly, Sir Henry, Tinkerbelle, Scarlett, George, Alanna, Mini, Meg, Luna, Flower, Belle, Mei, Mulan, Claidheamh mor, Sgian dubh, Norbert, Smaug, Firedrake.