The offers are being made by the Pinstripe Farming Company and United Ostrich Farming (Europe), both of which are looking to raise capital as the industry moves into a new phase of development.
Until now, most of the giant birds hatched in the UK have been kept to build up breeding stocks, but within a year farmers hope to be moving into meat production - first by supplying speciality restaurants and butchers and eventually through high street grocery chains.
Vince Tyack, owner of Brookfield Farm Ostriches at Stow-on-the-Wold, Gloucestershire, said he decided to try raising the birds in 1990 after a trip to Africa during which he considered other unusual stock.
"A good many thought I was mad when I got into it," he said in a broad Gloucestershire accent. "I looked at crocodiles but I thought `No, you've got to have the hothouses.' I damn near bought some camels in Tunisia, for tourism. But I didn't think there was as much scope as with ostriches."
The main attraction of the avians for farmers is that they produce five times as much meat per acre as beef cattle. A breeding trio, consisting of a cock and two mature hens, averages 60 eggs a year. The survival rate for chicks, from laying to three months, is 70 per cent.
Ostrich meat is popular in southern Africa, and more than 150 British farmers are counting on it catching on here.
Although the steaks, which are cut from the legs and back, have the look and texture of beef, the industry claims that they contain less fat and cholesterol than other poultry and even most fish.
The leather hides - usually 14 square feet - are also prized and there is a small market for ostrich feathers, although nothing like the demand that existed before the First World War, when the birds were briefly farmed in Australia.
Investors do not have to deal directly with the birds, which can be temperamental and are classed as dangerous animals in this country. Their kick is powerful enough to disembowel a lion. They can also be immensely time-consuming. Chicks hatched in incubators often imprint on their human carer, who then has to spend lots of time with them. Some hens cannot lay unless their human is present.
"We're inviting people to get into share farming," said Neil Cunliffe- Williams, Pinstripe's marketing director. "They'll actually own the bird." The minimum investment is £2,500, and raising the bird to maturity costs another £250. An adult is currently worth between £6,000 and £7,000. Both companies have arranged insurance to protect against the birds falling ill or proving to be infertile.
The biggest obstacle facing the ostrich farmers is a lack of licensed slaughterhouses. Red meat abattoirs are not allowed to process poultry, and poultry packing plants are not big enough to hang a 10 to 12ft ostrich carcass. Pinstripe hopes to build a special slaughterhouse near Stow by the middle of next year. Another firm is looking at building one in the North-west.
Also coming are new regulations on raising the animals. The Council of Europe is considering a draft document.
Clive Madeiros, a veterinary surgeon and author of Two Toes: The Practical Guide To Ostrich Farming, said not enough was known about the birds. The most common variety, the Black, has been domesticated for only a little over a century, while the Blues and Reds have been farmed for less than two decades.