chewing on wood is good! It helps keep their teeth down. The thing is it isn't long lasting and soaks up urine really fast so you may not own it for long before you have to throw it out. Also I think mites and lice can live in wood so it might be best to freeze it beforehand.
I decided not to do the wood house thing anymore and just give them wood chews. It's easier to clean plastic and fabric IMHO.
I made a two little homes out of wood. If you can make or buy one that has an open bottom the urine doesn't soak in because theres no floor to pee on. However if they get ontop of it, it might be a differen't story. I was worried about splinters too. I just keep an eye on what/where they chew. So fare nothing to worry about or report .
splinters shouldn't a problem. at least not with ingesting. the way a rat chews as eats there is no room for splinters. they grind, not crunch. this is why chicken bones are perfectly safe for them whereas are almost always a guaranteed way to get to take your dog to the vet for emergency surgery. i don't do the wooden homes or toys because of the urine soaking factor. it really doesn't take long for them to hold the ordour and there's no real way to get it out. i use plastic huts instead ahich can be popped right in the dishwasher or washed with the cage at the car wash and all odour disappears. for chewing and teeth care i give my rats chicken bones
I'm not sure if pellet feed is enough to keep their teeth down. Yeah I don't think I will use their wood hutches anymore, it was a first time rat owning thing back when I first got my rats. Now I use the plastic igloos.
But I do think you need something more than pellets to keep their teeth down. Perhaps raw hide or wood chews?
Personally, I don't like wooden houses for small animals. Urine and other liquids soak into the wood, and they're fairly impossible to really clean. Though, they are great for chewing and rats love them.
Rawhide is pretty nasty stuff, and isn't good for any animal, even dogs because it's really high in protein, and has no nutritonal value. A better option is Nylabone Edibles (low protein, they have about 1%). You can ziptie them to the cage bars, and rats love them .
Also, if you feed subee's mix, the dry pasta is great for their teeth.
I read i thing some were that dry pasta has shattered and cut there mouths so i part cook it first-maybe being a bit of a fuss pot!
I got yards and yards of Lino for Â£10 from the off cut bit in my local carpet shop, its great for covering the bars of the cage and its come in handy for creating a peramiter fence sort of thing in the "rat area" (they can get out if they want but they get told NO if they try and they seem to be ok with that). I think it will be an easy floor to clean with hot soapy water, ive used a torn up flanlet sheet for beding, furnature saver, hammocks, hide outs...