The Woodland Trust has objected to plans for a poultry unit to be created near an ancient woodland at risk from the emissions.
The trust urged people to write to East Lothian Council to reject the proposals near Begbie Wood, Haddington.
The development, put forward by Hamilton Farming Enterprises Ltd, includes a 140m in length, 20m in width and 5.5m in height poultry house.
"Although we support chicken farms utilising trees, when it involves damage to ancient woodland it’s not something we can condone," The Woodland Trust said.
"This is the case with the Begbie Wood poultry unit application in Scotland. A planning application for a free range egg production unit in the middle of ancient woodland has been submitted to East Lothian Council. If the plans go ahead it will cause direct loss and damage to over 16 hectares of ancient woodland."
The house, and its associated 16ha ranging area, can accommodate 32,000 free-range, egg-laying hens.
Disturbance to the woodland
"Ancient semi-natural woodland is an irreplaceable resource and, along with other woodlands, hedgerows and individual trees, especially veteran trees of high nature conservation and landscape value, should be protected from adverse impacts resulting from development," the trust said.
"As well as the direct loss to the ancient woodland, the site will be heavily impacted by the free ranging of the chickens, specifically the impact that the hens will have on ammonia concentrations in the woodland from their manure.
"The concentrations of ammonia will mean that any ground flora which survives the grubbing up from the hens will alter in composition due to the added nutrients on site.
"The hens will also cause disturbance to the woodland floor and one of the most important aspects of ancient woodland is its undisturbed soil.
"An Environmental Impact Assessment has not been carried out on-site; due to the impact to such a large area of ancient woodland, [we] request that the council ask the applicant to carry this out.
"At the very least, an ecological survey, which currently has not taken place, should be carried out on-site before a decision is made by the council."
