ANSWER: The Ark was considerably larger than a football field. It was 300 cubits long. (Although there were different lengths of a cubit, the standard was the length of a man’s arm from elbow to the finger tip, which averages about 18 inches.) At 18 inches that would make 300 cubits about 450 feet, which is one and a half times the size of an American football field. But the Ark had three decks. So, that would mean the Ark had the floor space of four and a half football fields. The cubic space of the Ark would have been roughly equivalent to 500 U.S.-size box cars. Imagine, 5 fright trains each pulling 100 cars! That is the space Jehovah designed into the Ark. That is more than enough room for two of every animal, including the birds of heaven and food for a year.
And, we do not know, the account doesn’t say, but God could have used juvenile animals that were not fully grown. For example, there is a huge difference between a juvenile hippo and a fully grown behemoth. And, again, we do not know, but God could have put many of the animals into a hibernative sleep for the duration, as most mammals have the capacity to hibernate although most do not under normal circumstances. That would have certainly alleviated the chore of feeding and watering and stall cleaning.
By the way, Noah did not bring the animals. Jehovah brought the animals and birds to him and God’s angel closed the door to the Ark.
Check out “Christian Answers” to the questions associated with the Flood and ark