I have found if I free range hubbards they consume roughly 10 kg from day old till dispatch at about 12 weeks, and on average producing a carcase between 2-2.5kg. They are on chick crumb for the first 4 weeks then grower pellets.
OK, just reporting back. We ran our birds on probably too long to 15 weeks, but went easy on the feeding at times to ensure none of them developed leg problems. The final dressed weight of the hens was around 2.5kg, with the cocks coming in at 3.76 to 4kg (Wow!).
In that time, they each consumed 2.7kg of chick crumbs and 12.2 kg of growers pellets (again, Wow!).
So, although ours ate 50% more food than Andrew's, they also weighed 33% more by the end of their 25% longer lives!! Our total variable costs including bedding, electricity and professional slaughter therefore came to just over £12 per bird. So, for an average dressed weight of 3kg, that's £4.00 per kg.
For reference, a Tescos standard bird is currently £3.43 per bird, whilst 'finest' free range or farm shop birds are about £6.00 per kg, so all in all not too bad I reckon!
Our new
mobile chicken coop also worked very well indeed. The lino flor was very easy to clean out, and two of us could wheel it about without any problems so we could keep the birds on fresh ground all the time. The other big improvement we made was to buy some of
these nipple drinkers from E-bay. I tried mounting them in a fixed length 2" overflow pipe with no success (you have to be able to raise them up as the poults grow), so in the end I just drilled holes in the bottom of an old salt-lick bucket, screwed the nipples in and hung it up for them. It was amazing how quickly they cottoned on to this, and it made a huge difference for minimal cost - no more soaked bedding or cleaning out mucky drinkers for us!

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I hope that's helpful folks!
Womble.
