I have an aviary with various birds and also kept quail with them.
It is quite the normal thing to do amongst bird keepers because they eat all the spilt seed that the other birds kickout.
Mine also had access to grit, oystershell, egg food (for extra protein), fresh fruit and veg and quail pellets. They tend to ignore the quail pellets and eat everything else. I have kept quail for years and they certainly dont starve to death. It is by their own preference that they dont eat the pellets.
Quails are quite smelly, more so than the aviary birds.
They do pace up and down alot and run around a lot, they are always on the go.
Some people keep them in rabbit hutch/runs. Mine were in a 36 foot long aviary, 7 feet high.
Whilst they can fly upwards to quite a height, I find it is only the young ones that do so.
I would never keep one bird of any kind on its own.
Male quails crow. You do not need a male quail unless you intend on breeding
Quails, like chickens, are not adverse to a bit of fresh meat / blood. Last year I lost several fledglings that the quail ate, which is why i no longer keep them.
They will also, like chickens, turn on each other and peck away at them if one is injured or weak.
Quails (females) will often have bald patches at the back of the neck and head. This is usually due to the male being over amorous. If there are males with bald patches, injuries, its probably due to them fighting with other males. Females will also fight amongst themselves if there is a particularly dominant hen. They can be quite evil.
Pet Shops
This is how they work, if you buy it / them, they will get more in to sell. I do also wonder if they prey on customers that will feel sorry for the weak, feeble animals kept in unpleasant conditions. They are a business after all and it is their job to make a profit. Pet shops are not animal rehoming charities.
and i feel that they will always put profits before care.