All gone

This is our neighbours silage clamp. At least it usually is but as you can see it is totally empty. All you can see is the pile of tyres which hold the poly cover on and some old black polythene lying around. In all the years we have been here we have never seen it as empty.

They have started to cut silage around here in places but it would seem there may be a shortage of grass at the moment.

Any ideas?