Whilst looking at the Murkimus thing earlier, I noticed something odd...
First of all: sometime I get 579 of 599 collected, sometimes I get 579 of 600 collected. Weird.
Secondly, pet totals: Pets at Max level 567 + duplicates (11) = 578. Not the 579 that I actually have. Rare pets does show 568, but all pets are rare and level 25.
I do have 579 pets, honest!
Other than that, I'd just like to say that this site is worth it's weight in gold for the "pet obsessed" out there! Many thanks