When I first got my hamsters (Sparkles II & Jar Jar Binks II, both Chinese Dwarfs), they made their bed in a house in their cage. Then they made a second open-air bed, more like a nest, and alternated between the 2 beds, but always sleeping together. Then I had to separate them, and the one that stayed in the cage they used to share hasn't been in the house since, and the one that went into a new cage instantly made a nest, and has never slept in the house in his cage. I've had hamsters before, but I'm no expert, so is this normal? They're both very happy, friendly & healthy. Thanks.