Orpingtons were originally raised for meat, but because they can be so friendly they've become a very popular backyard pet. Some of my orp hens weigh about 10lbs. Others are super-fluffy and only weight about 8 lbs.BTW I've always heard about orp being all feathers and fluff but I think they're lying to me. My old hen likes to be left alone, she was mostly raised by neighbor. I finally went to pick her up and much to my surprise she is all meat.
This is Big Blue. She's not even a year old and has a very solid build under her fluffiness. They grow until about 12-18 months old. I bet she's going to be a 10 pounder.
Below is Cookie. (bantam orp) When looking at her, she appears about the size & weight of a light to medium sized hen - like a Leghorn or Golden Comet. BUT, she's mostly feathers. She may appear to look about 5lbs but when I pick her up, she's only about 2.5 lbs. It's quite surprising.
Here's Cookie next to some LF chickens.... & one Sebright. She & the tiny sebright weigh about the same. Orps are a very docile breed, so my bantams can live with them.