The British Free Range Egg Producers Association (BFREPA) has re-stated its warning about over-expansion after bird numbers surged by a million in just a month.
BFREPA chief executive Robert Gooch described the latest increases in bird numbers as "crazy."
He said: "Industry data shows that between October and November an extra one million free range birds were housed.
"And we know that there is capacity out there for another million birds - so at some point over the next few months there will be another one million birds filling that capacity.
"Between November 2017 and November 2018 we saw an extra three million free range layers coming into the system," said Robert. "There is still too much capacity coming into free range.
"The growth in free range is far exceeding demand. Supplies are outstripping demand. With industry data showing that the number of birds has grown by a million in just one month, that is crazy."
The Department for Environment, Food and Rural Affairs (Defra) has just released its latest figures showing the recent trend in layer chick placings.
Whilst the figures show that in October this year placings were down by 5.2 per cent compared with the same period last year, Mr Gooch said that the more illustrative data was the average number of chicks placed per week by UK Hatcheries. This data showed a 13 per cent increase in layer chick placings.
"BFREPA has been alerting members about this for the last two years, but all we can do is let members know what is happening so that they can make decisions based on the data we have," he said.
"Our advice is that producers should think very hard before expanding production, given that the market is already in oversupply. They should certainly not be expanding without having a contract with a packer that they are happy with," he said.
Over-supply has led to downward pressure on the prices paid by packers for free range eggs - particularly medium and small grades.
Prices for large eggs have held up better because of increased demand from retailers and consumers for the larger categories. But both Noble Foods and Stonegate have announced price cuts in recent months.
During BFREPA's annual conference in October, Robert Gooch said that a tough summer had seen farm gate prices of free range eggs fall because of the oversupply of free range eggs whilst at the same time drought conditions had increased feed bills by 50 per cent for some producers.
He told those attending the conference that, whilst demand for free range eggs was growing at three or four per cent each year, supplies were increasing by 10 per cent, as new producers moved into the industry and existing producers expanded their units. He said this was unsustainable.
"At the beginning of this year free range became the dominant production system for the first time. That means we are now mainstream," he said.
"We are not a niche product any more. We need to accept as a sector that we are no longer niche and that we can't continue to expand and expand and expand. We are now a mature sector and the dominant production system.
"We have been expanding at 10 per cent a year for the last three years, two million free range hens going down every year for the last three years," he told those attending the conference.
"It has led us to the position we are in now where price is under significant pressure because of over-production."
Latest figures suggest that the national free range flock has increased by three million birds over the last year.
And Mr Gooch said he was concerned that some suppliers seemed to be suggesting that still more production was needed to meet the retailers' needs for 2025 - the deadline they have set for going cage-free.
At a recent open day at the new Northern Poultry Campus - a working free range egg production farm combined with research facilities for leading universities and educational facilities to train egg industry professionals of the future - Vencomatic, the company behind the venture, said that an extra 1,500 free range farms may be needed over the next few years.
"Approximately 18 million birds are still in cages, which produce eggs much more cheaply than free range," said the company in a briefing about the new centre.
"As the UK farming base moves toward free range, there needs to be a commercial and accurate assessment of how to do this. Free range egg needs to be produced with high welfare and as economically as possible."
It said: "With the shift from cage, there is a requirement for more free range farms. UK egg consumption is also rising by 4.4 per cent a year. Most poultry farms are 16,000-bird units. The UK may need another 1,500 plus poultry farms over the next eight years."
It said that, with 1,500 new laying farms and 500 new rearing farms needed, there would be a need for skilled farm workers. Most agricultural colleges had excellent provision for beef, dairy and sheep but very little for poultry.
At the BFREPA conference, Robert Gooch said that the industry already had enough free range units to meet the needs of 2025.
Following the release of the latest industry supply figures, he re-stated this belief. "I am very concerned about some equipment manufacturers and other suppliers into the industry promoting inaccurate projections about future requirements for free range eggs for 2025. They should read the report produced for us by ADAS."
He said all the evidence BFREPA had suggested that new free range production was not needed.