[racinghamster]

I would be more worried about him injuring his teeth if he is not used to a barred cage. Changing cages can stress a hamster sometimes and chewing the bars could be a sign that this is the case. If he doesn`t crave attention while in his usual tank, the barred cage has allowed him to change his behaviour and once they start to chew on bars, it can become stereotypical and dangerous. It`s a shame you didn`t have a perspex style cage or another tank to house him with only bars on the grill above.

Depending on how long he will be residing in this cage, if it means he is going to continue this learned behaviour, it might be wise to get a tank just so you can sleep and Ubi isn`t obsessed with any bars!