Small World your old pellets had 16% protein and 15% fibre I think you were right when you wanted to change them, for an adult it should be min 19% fiber and max 13% protein.
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Small World Complete Feed for Rabbits,
Ingredients: Wheat Middlings,Dehydrated Alfalfa Meal,Roughage Products,Corn Distillers Dried Grains with Solubles,Soybean Meal,DL-Methionine,Calcium Carbonate,Salt,Ferrous Carbonate,Ferrous Sulfate,Copper Sulfate,Manganous Oxide,Manganese Sulfate,Zinc Oxide,Zinc Sulfate,Cobalt Carbonate,Calcium Iodate,Sodium Selenite,Vitamin A Supplement,Vitamin D? Supplement,Vitamin E Supplement,Thiamine Mononitrate,Riboflavin Supplement,Niacin Supplement,Choline Chloride,Calcium Pantothenate,Pyridoxine Hydrochloride,Folic Acid,Biotin,Vitamin B?? Supplement,Yucca Schidigera Extract,Wheat Mill Run,Suncured Alfalfa Meal,Soybean Hulls (20%),Rice Bran,Soybean Meal,Corn Distillers Dried Grains with Solubles,DL-Methionine,Calcium Carbonate,Salt,Ferrous Carbonate,Ferrous Sulfate,Copper Sulfate,Manganous Oxide,Manganese Sulfate,Zinc Oxide,Zinc Sulfate,Cobalt Carbonate,Calcium Iodate,Sodium Selenite,Vitamin A Suplement,Vitamin D? Supplement,Vitamin E Supplement,Thiamine Mononitrate,Riboflavin Supplement,Niacin Supplement,Choline Chloride,Calcium Pantothenate,Pyridoxine Hydrochloride,Folic Acid,Biotin,Vitamin B?? Supplement,Yucca Schidigera Extract
Directions:
Instructions: Provide your rabbits with all the small world rabbit they will consumeeach day, or limit-feed as necessary To achieve the desired bodycondition. Clean the feeding cup daily And be sure To provide fresh,clean water at all times, small world rabbit is a complete diet. Hayand other forages can be fed, but are not required. Reminder: feed isperishable. Store this product in a cool, dry area away From rodentsand insects.
Feeding Instructions: Directions. Provide your rabbits with all the Small World® Rabbit they will consume each day. For some individuals, the amount of food offered may need to be limited to avoid obesity. Clean the feeder daily and be sure to provide fresh, clean water at all times. Small World Rabbit is a complete diet. Hay and other forages can be fed, but are not required. Nutritious treats can be offered on an occasional basis.
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Sherwood Pet Health Adult Rabbit Food have better percentage of fiber and lower protein so generally should be fine for your rabbit.
Maybe as you said you mixed them for a few days maybe you should do it longer for a couple weeks, gradually decreasing old and increasing new, but I can tell you pellets are not their main food and you can feed only hay and water for a week to make him less picky, then start with giving just a few pellets a day, then increase a bit.
On your old food package stated that hay is not necessary when you feed their product, that is not correct, he should have 80% of his diet hay and only 50 gram of pellets per day.
Especially now he's molting and if he won't eat hay hay is helping to push all the hair out, so if he doesn#t have enough hay he can get blockages, it's very dangerous.
Here's most popular rabbit foods in one table, Sherwood is recommended so it's just about transferring him slowly to it.
http://www.therabbithouse.com/diet/rabbit-food-comparison.asp
Most people on here as far as I know feed Oxbow and unlimited hay.
What is important, fibre must be min 19% and protein max 13% since your rabbit is an adult and can get fat if protein is higher. This is no good because he is not young and can have problems with cleaning himself and reaching his cecotropes etc, so as I said your choice was good just you need to make him eat those new pellets little by little.