Staying at Malfoy Manor under the eye of her sister took swallowing pride, and Bellatrix hadn't been able to choke it down. Grimmauld Place and the stench from the rat and the bat was worse, and therefore staying someplace else was the only option Bellatrix would stand for.
This, at least, managed a smile out of her, or what passed for a smile. "I'm certain we'll find something. Perhaps we may have to keep our pets alive for a time being. Pity that. I've never been good at remembering feedings."