This is our first time with chickens so any information will be greatly appreciated. We got 4 buff orpington chicks last Saturday (march 25th), and they're all eating and drinking very well. 3 of the 4 are growing like weeds and strutting around with new feathers. The 4th one just isn't growing that much, is now almost half the size of the others and has had issues expelling poop since we got her. Originally she had pasty butt so I cleaned her up really well and followed instructions from a lady at the feed store who's been raising chickens for 30 years- gave them some hard-boiled egg yolk (that they didn't really eat much of), and added electrolytes to their water. That seemed to clear up the diarrhea issue but now the little chick struggles to poop because it appears that her vent may have not fully developed open? The other 3 chicks have healthy looking vents, pink, a softish horizontal slit beneath their tail feathers, but this one's vent looks like 2 holes side by side. I read somewhere that one is the belly button but right after reading that I went in and she was trying to poop and it was coming out both holes? The poor thing pushes so hard and even squeeks a little while doing so. I've been keeping an eye on her since the pasty butt issue and the fact she's so little, but it hasn't really concerned me much because she runs around and plays with the others. I just had to help her pass a huge turd (sorry for lack of better wording here..) I'm assuming it was that big because it'd been blocked up there at her vent for a while. I massaged around her vent with warm olive oil which seemed to sooth her but when I put her back in with the others they won't leave her alone. Is this something I should be worried about? Any suggestions on what to do or expect will be greatly appreciated. Thanks in advance..