Yes, they do bring in the animals for maintenance to the animals & the savannahs, but when we were there, they staggered the savannahs so that at least one savannah had animals out at a time.
But, as posted above - the only lunch option at AKL is Mara & it's certainly NOT worth a trip all the way there for.
If I were you, I would make ressies for an early dinner at Boma. Get there about 30 minutes prior and go see the animals then. When we stayed at AKL we saw the most animals at that time. They were coming in to be fed. The added bonus is the Zebra Domes (dessert at Boma)!
Just so you know the only place at the AKL that serves lunch in Mara, which is the food court at the AKL. Also, if you are going at a time of year when it is hot the animals tend to relax in the shaded areas, ie farther away from the public viewing areas. I would reconmend you either do an early breakfast at Boma as the animals are very active in the morning or maybe a nice dinner at Jiko and check the animals out before or after that.