Once he'd heard that Stiles was going to bring the dog down to see him, Derek had made sure to spend some extra time doting on the dragons and had just fed them so they'd be sleepy and hidden them away with some of his dirty clothes to hopefully appease them, casting a silencing spell over their hiding spot so they wouldn't attract any attention. He'd made a batch of treats, since that was his excuse and all, and he made sure that any evidence of the dragons was gone before answering the door. His legs were promptly assaulted by a puppy and he smiled down at Batman.
"You got bigger, excuse you," he said, picking Batman up anyway. "Come on, let's go check on the other creatures since you were so helpful while you were here, keeping them all in line." He tossed his head to Stiles to indicate he could come along too, since hey, it would probably be educational, and started off towards the pens. "Good to see you up and walking."