I’m with Robin. I only buy free range or organic chicken (and pork). The one sitting in the fridge is free range, weighs in at 1.3kg and cost £7.29. Buying breasts would be a higher per kilo price of course.
I work on the basis that beef is grass fed so I’m less fussed about it having a higher welfare certification. And lamb (which features most often in this house) is inherently free range.