Today I took my boy to a Dinosaur museum, Rocky Mountain Dinosaur Resource Center to be exact. It's a neat place to visit and if you are traveling hwy 24 through Woodland park you can't miss it as there are colorful models of a T-Rex and a styracosaurus standing guard at the front of the building. If you go during the weekday you can also see the guys working in the lab as they remove bones from the rock and make casts.
After looking around for ourselves we joined in on a tour. Some pretty good information but I, as a creationist, took exception to one statement (tho I didnt argue it on the tour as the thought hadn't fully formed) The guide stated that the large Sauropodomorphids (the "long necks") were less advanced than "later" dinosaurs such as the hadrosaurids (including duck-bills) because the sauropodomorphids did not chew their food and instead used stones (like in a gizzard) to grind their food. Gizzards are a less efficient method than chewing, I am not arguing that point. To be honest I don't have knowledge of that myself but I can certainly agree to it.
The exception I take it that it is less efficient for a large beast, some of which weighed up to 110 tons, would find chewing more effective. If we drop it down to just half that and say 55 tons its really just a race to get food into the mouth and into the body. I can't imagine that there would be near enough time for a creature to chew the amount of food that would be required to feed such an enormous beast.
I do not know the calorie requirements of a dinosaur, and of course no one does. But I have seen stated that a reptile can survive on approx 10% the calories required for a similar sized mammal because of it taking on external heat rather than creating its own. Still this leads to a requirement of 220,000 calories a day for a 55-ton animal. And that is survival, not growing/thriving. The above number was reached at assuming only 2 calories/lb, which is the same amount of calories that is consumed by each lb of fat (in humans) each day. It would seem to me that the number for daily living would be somewhat higher but going with the number above that would equal out to be 500 McDonald's double cheeseburgers each day, or 50 an hour assuming 10 hours of eating each day. Or 785 cans of corn. or 3150 cans of green beans. I feel sorry for the Brachiosaurus stuck eating green beans! Of course these figures would all be doubled at a minimum for the largest of the Sauropodomorphids. Anyways, my point is that a gizzard would be a more efficient way of taking in and processing food when the intake is so high. One "might" even say an example of a perfectly designed creature.
Final thoughts:
There is a school of thought that the sauropods dwelt in water which helped support their weight. This could put an increased caloric demand on the dinosaur, even accounting for warmer weather.
There is also a theory that the earth was far more oxygen rich back in the time of the dinosaurs. It is hard to imagine how such large beasts could breather in enough oxygen otherwise but that they did so somehow is obvious.
There is yet another theory that there was less gravity at that time. Intriguing but I don't see how it is possible and I am not stating I hold this view, just throwing it out there for consideration. Some valid points are certainly raised with regards to leverage and mechanics. There are other statements in the link that are problematic. Maybe I will address those another time.