I've got several 11 week old chicks of different breeds. A few of them still have a fairly prominent breast bone, ( I can feel it under the feathers), and some like my Barred Rocks are plump. Is it normal for growing chicks to take awhile to fill out? They get free feed and treats, and all seem to be eating well with the exception of one, which I posted about in the 'emergencies' section. I wasn't ever able to get hands on with my Leghorns, but my new chicks are much friendlier and let me handle them, and that's how I've noticed this.