Need advice on outdoor hutch

[Polecat Lady 0]

A UK friend of mine is having trouble as rats have twice chewed through her outdoor hutch.  The second time her hob escaped and was later found after he had been injured when hit by a car.  He is recovering.  What type of hutch is best or what can she do to prevent rats from chewing holes in her hutch?

[The one 8,456]

I took the easy option and made mine out of ply sheets they come in 8 foot by 4 foot so that's the size i made it so there was less work cutting it only bad point is at 4 foot deep i need to use a hoe to clean it out as i cant reach the shavings using my small shovel , Other thing i would do is put it on legs stops vermin hiding under it and lets the air flow under it 

[Luckee legs 453]

Its incredible rats try to get in. I've not had them try to access hutches which are primarily ply and all off ground but they do make efforts to get into runs. Here they don't go for wire sections or thick ply 12mm , but where I used thin ply 4mm, rats have chewed through in the past 

[Polecat Lady 0]

Thanks to both of you!  I've passed your replies on to her.

[Franks dad 830]

Is it definitely rats trying to get in and not the hob trying to get out to find a mate ? I’ve had ferrets try and chew it’s way  out , but never had rats trying to get in …. That Would be Suicidal