I just use golf balls, leave a couple in each nest all the time.
I also go out at roost time and shove the pullets out of the nests so I don't have to go out at the crack of dawn to open then nests back up.
Tho I did start retraining by physically taking them out of the nests and placing them on the roosts after dark for a couple nights, then covered the nests for a couple nights and now just check every night when I close the pop door just before dusk, one hen - now laying, still wants to sleep in the nests a couple times a week.
Luckily I can access the nests without going into the coop and disrupting the roosting time.
I also go out at roost time and shove the pullets out of the nests so I don't have to go out at the crack of dawn to open then nests back up.
Tho I did start retraining by physically taking them out of the nests and placing them on the roosts after dark for a couple nights, then covered the nests for a couple nights and now just check every night when I close the pop door just before dusk, one hen - now laying, still wants to sleep in the nests a couple times a week.
Luckily I can access the nests without going into the coop and disrupting the roosting time.