Hi all, my husband and I have two 3yr old cats, bro and sis, been raised together with us since they were 3mos old. 2weeks ago, we decided we wanted to raise two more! So, we got two 4mos old sis kittens, and first two days, they had diarrhea and both used litter, but after that, one of the kittens decided they will only poo outside litter, she pees in the litter though. We cant afford to change the litter we use, our budget just wont allow it with 4 cats, anyone have suggestions? Thanks!