I have a kitten that is about a few weeks old (I think about 3-4) and he keeps farting but won't poop, I keep putting him in the litterbox to see if he'll poo but he won't ! He's eaten, he's peed, he's farted but won't poop! What's wrong with him ? & I can't really afford a vet but if that's the only route, I'll have to sadly give him away