yes, ferrets weren't made to eat vegetables at all. That would be like finding a vegetarian lion
There are several brands of ferret biscuits/ferret mix etc. that should be fed in a bowl like hamster mix for hamsters. Also.. cat food! Ferrets adore sachets of cat food (my friend's prefer Felix
)
Also, another good idea is egg, give them a boiled egg to eat. Or instead of getting a boiled egg, my friends ferrets sometimes get a raw egg, ferret mix, and cat food all mushed together in a bowl, and they love it!
Raw eggs are good for them... don't worry