Pullets Burying Eggs

My 8 older hens lay about 4 or 5 eggs a day in one of their two nesting boxes.

Six pullets about 13 weeks old have moved in with them (and the two young roosters). They're burying the eggs in the bedding in the nesting box. At least, I think it's the pullets because when I visit them in the afternoon to freshen up their food, all of the older hens are out in the yard doing their thing while the little ones are usually hanging out in and around the nesting boxes. Then when they hear the cracked corn flying around, they all come charging out for treats acting all guilty of something...

Anyone have experience with this behavior? It's not a huge deal, as it's pretty easy to dig through the "nest" and find the eggs, but it'll get interesting when the riot squad starts laying...

I do intend to add 2 more nesting boxes (for a total of 4) to the enclosure so there is enough space for everyone once the little ones get to laying.