I don't know why scientists and unbelievers do what they do. Most of them are not trying to scientifically prove that the flood happened, they use science to prove it didn't. If they were scientifically honest they would understand that between the salinity of the seas, the difficulty in determining fossil age, and the fact that there are sea fossils on top of the Himalayas, they would see that science in fact proves the flood. Science proves the earth as young, creation of man, and the flood, as a matter of fact. Scientists ignore the science and pervert it to suit their reprobate minds just as the prosperity gospel preachers pervert the scriptures to pervert the word. It stems from the same source: satan the liar and the father of lies
As for the baby animals, I do not think it was any harder to care for them than an adult. Each has their own particular needs. Some theologians believe God put a spirit of docility into them so they could co-exist with each other and with man during the flood confinement. After all, God sent the animals to Noah and they docilely walked into the ark under their own steam. Noah did not have to hunt or trap them. So it seems they were already operating under a command of God. (Gen 6:20). It is not hard to believe their docility extended to the months on the ark and didn't end at the door when they walked in.