Until about 2 weeks ago, my husband and I had a flock of 6 girls, all different breeds. They free-range all day long with regular feedings and kitchen scraps and then have a nice, secure warm coop for sleep/nighttime. Our Rhode Island (aka "Red," my favorite girl) decided to hop the fence one day and the dog on the other side got her and killed her. We asked the dog owner/neighbor if we could go get the carcass and also filled her in on what happened. A few days later, a NEW hen was in our yard. The neighbor replaced the dead chicken. (We were totally fine with 5 chickens and never asked the neighbor to replace the one her dog killed. Hey, if the chicken hops the fence ...) Anyways, this new chicken looks like a mix of about 4 different breeds and we've nicknamed her "RoadRunner" since she is so dang fast. She's not been accustomed to humans judging by her behavior and looks shocked whenever we are in the backyard and the rest of the girls run over to us and then follow us everywhere. She is slooooowly adjusting. Time will tell, but until then, a few questions: 1. Do all hens lay eggs? We are reasonably certain that she isn't laying, although we've seen her in the nesting box and then in the coop where the nesting box is watching our Brahma lay. Interesting dynamic. The RoadRunner loves the Brahma, for some odd odd reason. 2. Should we be introducing some sort of preventative antibiotic to the flock since we have no idea the conditions this new girl came from? If so, what? 3. In general, what should we be giving the flock to help prevent mites or lice or whatever? 4. She appears to be at least a year -- will a hen that age mix well with a more established, older flock? Thanks ahead of time to everyone who answers! I really appreciate any insight or similar stories and your experiences with strange chicken events!