I have a 4 year old deaf cat named Yeti that has recently started to refuse to poop in the litter box. I have two cats and three litter boxes set up one where I have to scoop and the other two are the fancier one like the puramax. I have kept them clean and haven’t changed the litter he has used in the past. From what I can tell he will pee in the litter box but not poop in it. I have taken him to the vet and the have ran test and said he is perfectly healthy. I have a theory that it could be separation anxiety because he will use it when I’m home but every day when I get home from work he has gone beside it. Is there anything I can do to help him?