Barley Straw addiction!

Dylan has a real taste for Russell Rabbit Barley Straw which I use for some of his bedding (instead of shavings). He really enjoys eating it but I'm not sure if it does his tum any good (he's 9 months old & had no tum problems *touch wood!*) - could someone advise me on that?
I don't want to get to a stage where he is ignoring his hay & just eating the Barley Straw but at the same time don't want to take out what he obviously enjoys eating & works well as a bedding - any help appreciated.

We were told by our vets that straw does not have the fibre and nutrients that hay has. Jimby went through a phase of eating all the straw and ignoring his hay so now we just give him hay.
Is Dylan an indoor bun or out door?
Indoor buns do not really need straw as extra warmth as they are protected from the wind etc.

It's not harmful, it just has no nutritional value. I'd be inclined to mix some hay in with it and top it with hay so he stands more chance of munching on the hay by accident. Barley straw is excellent for outdoor winter bedding as it is so soft and such a good insulator

I use this for the outdoors buns bedding area I put a thick layer of it down and then top it with hay I do notice the buns to munch on the straw too though. As said above it has no nutritional value

Thanks everyone. He is an outdoor bun but lives in a cabin (the straw is in the hutch that is inside the cabin) so insulation is good for colder days.
I think I'll give the mixing hay in with the straw idea a go in the hope it'll encourage him to eat more hay!