50-100 Cornish cross would poo a LOT in a 40 x 40 foot area. They poo more than regular chickens because they eat so much. It would be very nasty after 3-4 weeks.
One reason to do a moveable tractor is to handle poo. It would be much better to use electrified poultry netting, along with a simple movable structure than to keep them in one 40 x 40 foot area. That way you can also keep them in a much smaller structure/netted area. Many pastured broiler people move their small pens once a day, or once every 2 days. Then, you have no excess poo (it is all broken down quickly) plus the birds can eat fresh greens every day. It is a system that keeps the birds healthy.
You don't say what the ground/bedding would be in your 40 x 40 pen, but I think you will likely have more illness/deaths if the poo builds up. The one exception to this is if you have a bedding plan to compensate for the poo.
One winter I kept 20 broilers in the barn in a 10 x 12 pen on hay bedding because it was too cold for them to be on pasture, and I just kept adding a layer (2-3") of hay every 3 days and it worked well. the bedding just got built up higher and higher over time, but it stayed relatively clean with minimal poo.
Joel Salatin's book on pastured broilers gives you exacting measurements for this sort of question down to the tiniest detail.
One reason to do a moveable tractor is to handle poo. It would be much better to use electrified poultry netting, along with a simple movable structure than to keep them in one 40 x 40 foot area. That way you can also keep them in a much smaller structure/netted area. Many pastured broiler people move their small pens once a day, or once every 2 days. Then, you have no excess poo (it is all broken down quickly) plus the birds can eat fresh greens every day. It is a system that keeps the birds healthy.
You don't say what the ground/bedding would be in your 40 x 40 pen, but I think you will likely have more illness/deaths if the poo builds up. The one exception to this is if you have a bedding plan to compensate for the poo.
One winter I kept 20 broilers in the barn in a 10 x 12 pen on hay bedding because it was too cold for them to be on pasture, and I just kept adding a layer (2-3") of hay every 3 days and it worked well. the bedding just got built up higher and higher over time, but it stayed relatively clean with minimal poo.
Joel Salatin's book on pastured broilers gives you exacting measurements for this sort of question down to the tiniest detail.
Last edited: