Well, yes, when they are that small they don't seem to know to go inside at night. I always shoo them in for a few weeks to make sure they know. But they still should know to go inside to warm up or find their feed and water.I regulary had to put them in the coop in the beginning. And always have to do the same game, everytime I have chicks. They just huddle outside as well. They get the hang of it, after a couple of days, Was never the ramp, they just had to learn to go into the coop at dark.
This year they all seem to have figured it out early. Last year I had to put them inside for weeks! I guess every year and every hatch is different.