Not really unless you have some how cut the spawn points.

Which is possible. No raids till day 30 isn't uncommon. I had that happen. I had no raids till after I killed the first boss. Which was about that point day 30 or so.

No greylings is a bit odd. As long as you have all the other spawns it may just be that you are cutting trees down and their isn't a spawn close but that seems unlikely as they have crossed large rivers to get to me.