I guess there are pros and cons to both Gatorade and Durvet Vitamins and Electrolytes. Duravet has vitamins that Gatorade does not have, and no sugar, but it has an alarmingly high level of sodium when compared to Gatorade. 37% of an 8 oz packet of Durvet is sodium. That's 84 grams of sodium, or 84,000 mg of sodium. Gatorade has 100 mg of sodium and 5 grams of carbs (5,000 mg of carbs). So, I don't think the sugar content of Gatorade is as big of a deal as some are suggesting (considering one gram is the equivalent weight of a paperclip). If you throw out cracked corn occassionaly, you are giving your chickens the same amount of carbs (5 grams) as Gatorade. I personally consider 84,000 mg of sodium a bigger issue to be concerned about than than 5,000 mg of sugar. I think sodium is a cheap ingredient which is why Duravet has 37% of its product as sodium. Your chickens are already getting 68,000 mg of sodium from chicken feed, so if you give them Duravet on top of chicken feed, then your chickens are consuming 152,000 mg of sodium (152 grams, or about 1/3 pound of sodium). I personally think that is too much sodium--you might as well stick a salt block out there.
Duravet: 0 carb, 84,000 mg sodium
Gatorade: 5,000 mg carb, 100 mg sodium
Cracked corn: 5,000 mg carb, 23 mg of sodium
Purina Layena: 0 carb, 68,000 mg sodium
I guess someone could break the portion size down to what an individual chicken would receive, but I'll leave that up to someone else.