i think whether silkies roost or climb or not just depends on whether they're used to it, and whether you have bigger birds to show them the way. i started with 15 chicks, 6 of them silkies. all the silkies roost which means they climb up two planks to get to their 4' high roost. (none of the birds have to fly up to the roost). they have no problem with it. they'll occasionally sleep on the ground, but they're perfectly fine going up on a roost. OP didn't say whether the 5 silkies are you only birds, probably so. but if you have other breeds the silkies will catch on (eventually).