Didn't EBD breed alsatians at one point? I seem to remember something in one of her newsletters. She may also have had at least one spaniel.
Interesting about the Alsatians, Audrey - you'd certainly think so from They Both Liked Dogs
, and to a certain extent The Lost Staircase
. Helen McClelland's Behind the Chalet School
refers to EMBD's pet Alsatian, Bryn and cocker spaniel Sarah, as well as her cat Bobby, and a friend's remark that "Elinor really preferred all cats and dogs to any of her friends"...
The Pets prefect is mentioned a couple of times over multiple books - Eva von Heiling holds the position when Joey is Head Girl, with Louise Redfield as assistant in the last term, and Ida Reaveley takes it when the schools merge. In Lintons, the "usual activities" for the term include Guides, Hobbies Club and Pets. So it's a fairly consistent throw-away line!
Though the "throw-away line" referred to was actually "Some of the babes have canaries with them, but their House Mistresses will see to those." - and made as indicating that their care would be nothing to do with the Pets Prefect...