It's tragic for the birds, and, not least, farmed birds. There have been massive kills of farmed birds, some in the US by turning off ventilation and allowing the birds to die of heat stroke. Unspeakable cruelty underlies our meat consumption.
That rather horrible example apart, you presumably know very little at all of UK meat production.
Sheep meat is 100% free range.
The huge majority of cow meat is free range, although farms with land that will not take cattle over-winter, will house stock for the worst of the weather.
Pig meat - buy UK freedom standard. Farrowing crates have been illegal in the UK for quite a considerable time.
Chicken meat - plenty of options, from intensive to free-range.
Free range is not as cute and cuddly as it sounds, especially for poultry. In many egg units, the hens choose to stay in the shed, especially in rubbish weather. They are also open to every disease possible, and predation.
There was an indiot on R4 this morning, from the National Trust. Apparently, the ltest strain of bird flu evolved in intensive poultry units in China. I should love to see the proof of that. It may well have been IDENTIFIED first in poultry units................... Here in the UK, wild birds have brought various strains into domestic stock. The also went on to suggest that there were various things that could be done to stop spread in wild birds - total fantasy, very sadly.
Different species involved, but I strongly suspect that the mortality rate in wild birds due to bird flu, is WAY less than that during the 1964-65 winter.