An investigation by Sky News and Viva has uncovered evidence suggesting Britain's largest egg producer is contravening strict guidelines on animal welfare.
Noble Foods own hen farms accredited to the RSPCA Freedom Food scheme, designed to offer particularly high standards of welfare for farm animals.
But footage obtained by Sky News and Viva from two farms in Fife, Scotland, suggests the guidelines are being breached.
An employee for Noble Foods was covertly filmed revealing electric wires are used to control the hens, who are also encouraged to remain indoors until 80% of them are laying.
Another worker admitted at least one barn was infested with red mite, a parasite that causes skin irritations.
On a second visit to the farm, investigators filmed dozens of birds which had lost feathers due to disease and being pecked by other hens.
For their Happy Egg brand, Noble Foods portrays an image of welfare standards beyond the requirements of the Freedom Food scheme.
Justine Kerswell from Viva
The investigation into The Happy Egg Company shows a very different picture - one of disease, incarceration, short lives and electric shocks.
The company's website states hens are given activities to enhance their natural surroundings such as "an adventure playground and sandpit".
Yet on two separate visits to the farm Sky News discovered muddy surroundings and a water-logged sandpit.
A Noble Foods worker was recorded admitting the farm had problems with soil drainage and conditions for the hens were different to those officially portrayed.
Justine Kerswell from Viva, told Sky News: "Contented hens pecking at the ground and enjoying a dust bathe in the sun - that's most people's view of free range egg production.
"Viva And Sky News' investigation into The Happy Egg Company shows a very different picture - one of disease, incarceration, short lives and electric shocks."
In a statement, Noble Foods said: "We take the treatment of our hens extremely seriously.
"As soon as we were made aware of the video footage the company instigated an internal enquiry.
"Last night, at our request, both farms involved were audited by RSPCA Freedom Food inspectors and both were given very positive reports.
"We will continue to work with RSPCA Freedom Foods to ensure the highest possible welfare standards across our farms."
The RSPCA told Sky News they take any potential breach of welfare standards very seriously and would be suspending the farms in question from the Freedom Food scheme pending their own investigation.
Sainsbury's welcomed the RSPCA investigation while Ocado have announced they will de-list Happy Eggs from their range as a precautionary measure.