I really like the skewer kabob ones with the clear ball at the end. I stole a couple from Jeanne for Folger too. I can just refill them indefinitely it's nice and they are so much easier to do than trying to string everything together. For the shelter I have two sets...the ones I'm filling and the ones in the bird cages and I just collect the empty ones every time I'm at the shelter and replace them with the other set. I can do about 5 of the big ones right now in an hour and a half.
Though April and Giz seem to destroy two a day so it's hard to keep up with them lol. Those are the Amazon and cockatoo in the pictures.