Yes, quite high.  One GSD could finish a pack of 15kg in 2 weeks.  Averagely around RM300 per month in terms of dog kibbles.  But don't feed your dog 100% on dog kibbles, not good for health in the long run, you should combine with homecook holistic style & kibbles.  Then your GSD condition will be good in terms of fur coat and healthy in weight.

Holistic style mean you could cook rice with meat (without salt/kichup/seasoning) plus some vegetables i.e. potato, carrot, green veg, garlic etc.  And sometimes give them raw meat.

Same for all the dogs.