I think it would actually be the pellets that you should limit as opposed to the seed and nut mix. They're known for over-doing it. I would rather give them like you would a supplement, a little a day if you absolutely have to feed them. You can feed them a complete diet through just fresh foods, cooked grains and pulses etc. as well as their seeds and nuts. I would rather go as natural as possible. We don't have Roudybush here in the UK so I can't tell you much about that, but this is what has started to put me off Harrison's...
Ingredients: *Ground Yellow Corn, *Ground Hulless Barley, *Ground Hulled Millet, *Ground Soybeans, *Ground Shelled Peanuts, *Ground Shelled Sunflower Seeds, *Ground Lentils, *Ground Green Peas, *Ground Toasted Oat Groats, *Ground Alfalfa, *Ground Rice, *Chia Seeds, Calcium Carbonate, Montmorillonite Clay, Vitamin E Supplement, Ground Dried Sea Kelp, Sea Salt, *Sunflower Oil, Natural Mixed Tocopherols, Lecithin, Rosemary Extract, *Algae Meal, Vitamin A Supplement, Vitamin D3 Supplement, d-alpha tocopheryl acetate, Vitamin B12 Supplement, Riboflavin Supplement, d-Calcium Pantothenate, Niacin Supplement, Pyridoxine Hydrochloride, d-Biotin, Thiamine Mononitrate, Folic Acid, Zinc Sulfate, Manganese Sulfate, Copper Sulfate, Sodium Selenite, Calcium Carbonate, *Vegetable Oil.
*CERTIFIED ORGANIC INGREDIENT
Guaranteed Analysis: Crude protein (min.) 14%, crude fat (min.) 6%, crude fiber (max.) 4.5%, moisture (max.) 10%.
Yup. Not all organic at all so I think it's pretty darn bad to claim that they are 100%!
Here's some more info about Totally Organics. These were definitely my favourite to use! They crumble quite easy which some birds might be a bit funny about BUT Harrison's is as hard as pellets come, IMO
It's entirely up to you what you decide to feed any of your birds, but I'm just going to say my opinion
Regarding disease testing, if you do offer to foster him ask if they will test for psittacosis before hand, at least. It's an inexpensive test and IMO is vital if you've got other birds around. Sadly, it does not matter if they are in separate rooms or not, it can spread through dander. Dander can get everywhere
. My Indian ringneck parakeet, Echo, caught psittacosis from my outdoor cockatiels! I had been working in there when we took on Cin (the bird who bought it into the flock who is ironically still alive when nobody else is!) and obviously I never thought that I would be cross contaminating after washing my hands. But nope. She got it anyway. To do quarantine properly you would need an entirely different place with separate air space and you'd have to disease test. Obviously that is an unrealistic expectation for most bird owners as they can't provide that, however, you can disease test. If the rescue aren't willing to at least test him for psittacosis then I would leave it, if I were you. It's entirely up to you, I'm just saying from first hand experience