I don't block nests with chicks but I don't generally need to block them. It doesn't hurt to block them but be ready to remove them a few weeks before they come into lay so they can explore them.I imagine keep them acclimated to the coop with nesting boxes blocked as to not let them pick up the habit of sleeping in that space? Also keep roosting bars away for a bit until 6/7 weeks so they can get used to those and not potentially injure themselves?
How high are the roosts? Even 2-3 week old chicks can easily slow their descent by flapping and I think it's fairly rare to have fall injuries as long as they have room to flap and landing space to stop on.
I'm a fan of doing that with chicks, provided you have enough space, natural light and ventilation in the coop for them to use during that time. If your coop meets or exceeds the recommended 4 sq ft per bird minimum then that should be plenty of space to house chicks for a week or two.Was also reading somewhere to keep them in the coop for a several weeks before access to the run so they associate the space with home to come back and roost at night fall - picking up a good habit of returning to roost. Thoughts on this?