We just got done with pasty butt in our new chicks (shipped). You need to clean their butts twice a day until the butt stays clear otherwise they have a build up of faeces behind the 'plug'. I find the first time or two takes forever to soak the big hardened poops off, but the olive oil really does help a lot. I just use a fingertip and smear it on. I do find that cochins are a pain with pasty butt ... probably all the extra down to catch the sticky poops
but if you keep at it they are just fine. I dry their rear end with the lowest setting on my hairdrier for a while before putting them back in the brooder.
Drafts are a killer for baby chicks! Probably a big part of your problem... hopefully the new accomodations are going to work better for them. I found that if it is really cold eg at night, then I partially cover the brooder (being super careful of course to not create a firehazard) and that seems to help a lot with bringing the temp up a bit and stabilises it too. Good luck figuring out all the twists and turns
let us know how you go.
Drafts are a killer for baby chicks! Probably a big part of your problem... hopefully the new accomodations are going to work better for them. I found that if it is really cold eg at night, then I partially cover the brooder (being super careful of course to not create a firehazard) and that seems to help a lot with bringing the temp up a bit and stabilises it too. Good luck figuring out all the twists and turns