My piggy was sick the last couple of weeks, but these days he was doing better. I noticed that he makes a certain sound while he is in his cage. I recorded him, but in the recording he is in my lap. Sometimes he makes that sound after eating or when eating. I am talking about the deep one. Is that something to be concerned about? He was on antibiotic recently. I don't know how to explain that sound, but he wasn't doing that before.