If it makes you feel any better, Basia has eaten my underwear several times. I only ever knew when I saw it come out the other end. So if he was chewing apart a toy and the pieces were small enough for you to miss, chances are it'll just pass through. Usually if there's a blockage there will be vomiting and no pooping.
Also, he went from eating the most delicious raw food to what probably tastes like cardboard. I just looked up the ingredient list of Royal Canin, granted this is the "hydrolyzed protein" diet (I couldn't find the hypersensitivity one) but if it's anything similar, no wonder he doesn't want to eat it.
There isn't even an animal protein source!
Brewers Rice, Hydrolyzed Soy Protein, Chicken Fat, Dried Plain Beet Pulp, Natural Flavors, Monocalcium Phosphate, Sodium Silico Aluminate, Vegetable Oil, Calcium Carbonate, Fish Oil, Fructooligosaccharides, Potassium Chloride, L-Tyrosine, Salt, Taurine, Vitamins [Dl-Alpha Tocopherol Acetate (Source of Vitamin E), Inositol, Niacin Supplement, L-Ascorbyl-2-Polyphosphate (Source of Vitamin C), D-Calcium Pantothenate, Biotin, Pyridoxine Hydrochloride (Vitamin B6), Riboflavin Supplement, Thiamine Mononitrate (Vitamin B1), Vitamin A Acetate, Folic Acid, Vitamin B12 Supplement, Vitamin D3 Supplement], Choline Chloride, Marigold Extract (Tagetes Erecta L.), Trace Minerals (Zinc Proteinate, Zinc Oxide, Ferrous Sulfate, Manganese Proteinate, Copper Proteinate, Copper Sulfate, Manganous Oxide, Calcium Iodate, Sodium Selenite), Rosemary Extract, Preserved with Mixed Tocopherols and Citric Acid.