Bar-chewing can be a common behavioural problem for degus, and it is most often linked to either having too small a cage size for their needs, or to not being let out for exercise on a regular/routine basis, or a combination. Therefore, these two things should be looked at first in order to help them. Cage size can be checked to see if it's OK for the number of degus you have, by using the online cage space calculator on the housing page of Degutopia's site: www.degutopia.co.uk/deguhouse.htm . Degus do require a lot of space to perform a full range of normal behaviours, and can suffer with over-crowding, so it's really important to check this first.

Also a suitable running wheel, of at least 12 " diameter, is an essential in-cage piece of kit for your degus, they do need a lot of exercise throughout the day. Running and walking is an important part of normal degu behaviour. This is also linked with being let out for play time exercise regularly, but most important is doing this on a routine basis. Degus thrive on routine and knowing what to expect and when, so if you use the same time of day, every day to let your degus out to play (for at least half an hour), this can really help decrease bar-chewing behaviours. You may notice a little bar-chewing around the door of the cage just before your degus' normal play time, as they eagerly anticipate being let out to play!

I would also recommend that you let them out to play in the evening before bed, so that they work off their extra energy and sleep through the night as they should. Also, feed them their daily hard feed portion (www.degutopia.co.uk/degudiet.htm) in the morning, rather than in the evening, but as always provide free access to hay.