Depends if they are hens or roosters, I can't tell. Possibly hens, if so then yes they will lay. They will eat chick crumb and corn, offer bird grit too. They will eat table scraps - easy on the bread, and no citrus . bald patches are worrying... they shouldn't have those. They are possibly mites (white grains of sugar like creatures) around bum and under wing creases. Or could be from other chicks pecking at them if they were kept in a small coop with lots of other chicks. Search this site for stuff.... its a brill site and will tell you all you need to know.
Hello from Oregon & welcome to BYC. White leghorns? the lighting is dim. If they are hens you will get eggs. You can get food at your local feed store.
They look about a month old I guess, maybe a bit more. I'm not sure though. You'll get eggs from the girls when they're about 4 months old.
You can get chick starter from the feed store. If they're eating chick starter you don't need to provide grit, only if you're going to give them treats as well.
I hope you find any info you need here,a nd enjoy the site.
Good luck with your chooks.