I think you have Leghorn and Plymouth Barred Rock. Both nice breeds. I suggest that you don't add any more birds to the set up you have. It's about right for 2 birds. Any more, and you are likely to have behavior issues. If you need info on any topic related to chicken keeping, click on the search bar at the top of the page and type in your ? or key words. Then, you'll have to sift through the threads for information that seems appropriate to your situation. By the looks of your birds, they are just starting a molt. Most likely that's why they were dumped. Unfortunately, there are a lot of people who should never be allowed to keep animals. The ones who dump their pets are at the top of that list, IMO. Topics to consider: Fermented feed. Deep litter. Enjoy your little flock.