I have some destructo bunnies myself. I find that Guin likes to dig up the litter box. She does that in phases. When she starts digging at the litterbox, I give her a separate box with a deep layer of hay, and she gravitates towards that. She has a great time tunneling and popping out of her hay pile.
I use puppy pee pads on the floor for Lancelot who is incontinent. a layer of pee pads, a layer of human bed pads, then another layer of pee pads. This week Guin has taken to digging up the pee pads at the door. I don’t want this – because I can’t have Lancelot soiling my carpet. So I’m trying to encourage her to leave the bunny room through the bunny flap that she and Lancelot used to use, but since his health deteriorated, he doesn’t use it anymore. She won’t leave the room on her own without him. I have birds flying loose in the room, so I don’t leave the door open. They have a screen door with a bunny flap. So This weekend I am going to start picking Guin up and putting her in my room, where she used to enjoy running around – to try to burn off some of that excess energy (and fat!).
Avalon and Morgana used to rip up the puppy pee pads in their litter box, so I removed them. Now they just get wood pellets and a fresh layer of hay.
Morgana had herself litter trained by 2.5 months. She and Avalon have always been really good about it.5 months is still kinda young – are they spayed/neutered? If not, their hormones could be causing the litterbox training issues. If they are already fixed (kinda young so I assume not), then I would take them to the vet for a health check, and add extra litter boxes in the corners.
Guin’s favorite toy is one of those metal sticks that you can spear little objects onto. It has apple sticks, wooden shaped colored carved fruit, a lava rock, and a bell. She likes the lava rock and the bell the best. She tosses it around for the jingly sound, and nibbles on the lava rock. She likes destroying willow balls, but they are expensive to replace. Other than that – she doesn’t play with “toys”. She likes to toss around towels and baby blankets, so those are toys, but because of Lancelot’s incontinence, I give her smaller dish cloths that are easy to wash.
On the other side of the room are Avalon and Morgana. Destructo bunnies supreme. They like to chew on a sisal dig pad I made for them. My bunnies all have a sand box. These two will shred carpet, linoleum, cardboard, towels, and fleece veterinary bedding. So I give them sisal rope and pine objects. They chew their pine house, the pine untreated 2×4 lumber that protects the floor molding.
I know the regular advice is to change things out and provide plenty of toys. But I can agree with you that sometimes it doesn’t seem to make a difference. With destructo-bunnies, we need to find something that they enjoy destructing, and change that thing out – when they move onto something else. Like Guin with her destructive phases. Avalon and Morgana are ALWAYS destructive.
I would try an additional box with deep hay to deter Marshmellow from destroying Jelly’s litter box. You could also use shredded paper, towels, a bunch of cheap wash cloths/kitchen cloths dumped into a box, something for Marshmellow to burrow into.