Allotment and Vegetable Gardening

This may sound stupid but...

I have normal nest boxes which I line with straw.  There are 6 nest boxes, 17 hens and I get 12 - 13 eggs per day.  The hens tend to use only 3 of the nest boxes and as the weather gets wetter I know that will be treading on previously layed eggs and making them dirty with their muddy feet.  So, I thought the roll away plastic nest inserts would be good, they wouldn't be treading on the previously layed eggs. 

My question is do I leave the straw out of these to allow the egg to roll away and will the hens still lay in them if there is no straw in there as that is what they are used to?

Another question to anyone who already used the plastic inserts, how many eggs have room to 'roll away'.  Sometimes I get 6 or even 7 eggs in one nest box, whould this be a problem?

Cheers, Samantha 

looks good, the plastic insert ones are much cheaper though but the bit the egg rolls into looks a smaller than on yours, it's not easy to get a true idea of the size on the web-site. 

At least the hens use them without straw tho, did yours used to have straw before?  did they not mind the change?

thanks, gradual change, good idea!