I found this at the Dollar Store! It's actually called a bird suet holder, but wow do my pigs love pulling hay from it. I refill it just about every other day.
I have the exact same one! Only aparently I got gipped, LOL, I paid 4$ for it at the petstore. On I broke one of the sides so it just kinda sits open a bit, lol, but my Nismo loves to run under the opening like a tunnel
I have those, too! I have a bin under each suet feeder full of Carefresh so when they eat hay they sit in litter and it contains some of their mess (the girls more than the messy boys).