So far, housing restrictions for free-range birds have been limited to 45 units in Scotland’s wild bird risk area.

But what are the challenges of housing free-range birds?

A producer well-placed to answer that is David Brass of Penrith-based Lakes Free Range Eggs.

He knows only too well after being caught up in the 2001 foot-and-mouth crisis on the family’s beef and sheep farm.

“We were already selling eggs to supermarkets and foodservice customers from our own 27,000-bird flock at the time when foot-and-mouth came.

The whole lot faced shutdown,” he said.

A neighbouring farm had a suspected case and a Form D restriction was placed on all units within a 3km (1.9-mile) radius.

“It was a nightmare – nothing allowed in or out, no staff movements – everything just came to a halt overnight.”

The unit could have suffered badly were it not for the co-operation of the local State Veterinary Service.

“The local contact John Kelsey came with a ‘can do’ attitude and that helped,” he says.

The livestock was culled and the poultry put under restriction including being housed.

“The first few days were the worst.

They naturally wanted to be outside during the day and crowding around pop-holes was a big concern to avoid suffocation.

“Fortunately the disease took hold in March when daytime temperatures were low.

Natural ventilation kept birds comfortable and we tried to occupy birds’ time to reduce feather pecking.”

Measures included putting out fresh straw and spreading scratch wheat to encourage foraging.

The key time for staff to be attentive to risks of crushing and suffocation was between 7.30-10.00am.

“It was more of a problem with older birds used to a routine.

But even they became effectively a barn flock within a few weeks.

Mortality was low.”

As spring gave way to summer, pop-holes had to be re-opened and covered with wire to aid ventilation in the sheds as daytime temperatures rose.

Early days saw egg counts down, but birds soon settled and a change in overall production was not apparent.

Before the recent case of avian flu in Scotland, vets were also keen that producers put the risks and impact into context.

David Shingleton of St Davids Vets, Exeter, said the industry has lived and coped with disease requiring confinement, such as Newcastle disease, for many years and, as such, avian flu should be no different.

“I cannot get excited by this as it’s a disease that’s been around for many years.

Producers have experienced shutting up birds for three weeks for a Newcastle disease outbreak and it may well be similar for avian flu.”

Welfare issues will arise, but use of subdued lighting will help overcome the key concern of feather pecking and good ventilation will reduce risks of disease, he added.

“It will be an issue for smaller operators, but larger units will more or less take it in their stride.”