Hens have stopped eating !!!

Hiya

After a bit of advice. I've had my hens for just over a month now and they've been happy eating layers pellets. They're free range and have about 2 acres to roam around in so bugs galore ........ however over the few days egg production has significantly reduced and I've noticed they're not paying any attention to their pellets which are available all day...... they go crazy over the corn I give them once a day and I was wondering if I can up the amount of corn they have as well as leaving the pellets out or if there would be another reason that they're not eating

They all seem very happy and 'bok' away......any advice please

I've only had mine a fortnight, but can already see that pellets/mash are last on the menu, though that's all they have till mid afternoon, so they are all tucking in, though they have limited free ranging.
Corn is snatched out of my hand before I can put the dish down, in fact have to beat them back to get through the gate, so I've taken to measuring out a daily ration.  I read somewhere 20gms each per day, and that's their lot!
Had a bit of a dip in eggs (before I stated rationing), but now right up again. Yesterday 7 eggs from 8 girls.

I did think about checking around to see f they are laying elsewhere........but the thought makes my legs ache They spend a lot of time on the compost heap but haven't seen eggs there yet........ Will continue to contemplate looking all over......at least I'll get some exercise