Eggs are good, but I wouldn't call them well balanced because they have almost no carbs (although since most of us eat too many carbs in practice eggs are better than milk). I would definitely recommend kefir over milk anyway because it is much easier to digest. With an additional source of vitamin c you could probably live on only kefir indefinitely.
e: It looks like if the dairy cow has a diet with grasses with vitamin c (such as citronella) cows milk can have sufficient vitamin c to not only prevent scurvy but also meet 100% of RDA for vitamin c if it were the only thing you ate, so you could probably live exclusively on cow or goat milk kefir as long as they had a varied grass diet.
Eggs are good, but I wouldn't call them well balanced because they have almost no carbs (although since most of us eat too many carbs in practice eggs are better than milk). I would definitely recommend kefir over milk anyway because it is much easier to digest. With an additional source of vitamin c you could probably live on only kefir indefinitely.
e: It looks like if the dairy cow has a diet with grasses with vitamin c (such as citronella) cows milk can have sufficient vitamin c to not only prevent scurvy but also meet 100% of RDA for vitamin c if it were the only thing you ate, so you could probably live exclusively on cow or goat milk kefir as long as they had a varied grass diet.