I have 6 hens and 4 nest boxes: two in each of two coops since they are two distinct "flocks" (the first 3 are a year older than the newbies) - but they share outdoor space. The three older hens lay in "their" nest boxes and one of the new hens waits until I let them out and then goes into the older birds' coop and nest box and lays there too. One of the newbies lays in the "new" nest box in their new coop. One of the newbies has not started laying yet. We shall see what she decides. In any case, it appears that they are happy to share and there is one particularly attractive (to the hens - I can't tell the difference) nest box they all like to use. They wait in line unless the egg is imminent.
I use straw or hay in the nest boxes. They never pollute the nest boxes and the hay/straw stays clean and dry. They also like to pick up bits of straw and put it on their back after laying - some primitive instinct - and I am not sure they would do this with shavings. Shavings are great for areas where they relieve themselves but I prefer straw or hay for the nests. Others thoughts?
S.