Sunshine is always important and as can be seen here, the heath of Bill's tipplers are certainly not going to suffer because of all the wonderful sunshine and fresh air they receive.  The front doors to the loft have screen doors for plenty of fresh air.

This is the backyard loft of Bill Murphy.  As you can see, it doesn't require that one have a big loft operation to do a little Tippler Flying. 

The birds no doubt really enjoy the good fresh air & sunshine.   Although, typically, the birds in competition are kept in kit boxes which are isolated in such a way that the birds cannot see each other until they're released and in the air.  This prevents mating and egg-laying which can be detrimental to a good competition day.