Toby is our second Border Collie. We eventually successfully raised our first, Eazi, who sadly died at 14.5 years of age two months ago. We learnt a lot about the unique qualities and problems of BC's, but there is so much to learn. Toby is now 7 months old. We've had him since he was 4 months. We take him to behaviour classes every Sunday morning. He loves it and we are being trained well. My husband and I take turns in walking him every morning at 6am. We walk him 6 kilometres and incorporate training into that time. He also gets 15 minutes off leash in a park where he plays with other dogs. This takes about 1.5 hours. My husband works from home most of the day except when he goes out to meetings. We are training Toby to stay at home in the family room with his toys, chews, kongs etc for periods up to 3 hours. He has a play pen which we also use but as he jumps out of it, it is now more to put around the lounge to prevent him sleeping on that when we aren't there. Our two adult children also walk him when they are at home and he has a short 20 minute walk every night after dinner. He is not allowed the run of the house as our first border collie was, nor is he locked outside for hours. So, what is the problem? On Sunday afternoon he started eating one of our plaster walls. I sprayed the area with 50/50 mix of citronella oil and water which has always stopped him chewing wood. This didn't seem to work. We moved the child gate 6 inches to put the hole on the other side of the gate. This worked until today, Tuesday. He has now started eating the wall near his bed. He doesn't just scrape the plaster out. He is actually nibbling with his teeth and eating it. We haven't caught him in the act yet so can't tell him "no" or use our water spray if he doesn't stop after two "no's". I'm going to try tabasco sauce spray, but if this doesn't work am not sure what to do. He does this when alone in the downstairs area but someone is upstairs working. Does anyone have any ideas?