Keeping me awake at night.

FlutterinBantam

Not really!!

Why is it when we see "horse feed" for sale but it's "dog food" or it's "pig feed" and "cat food".

WTF!!! cannot figure it out.

The Raven.

Good point! It might have something to do with quantity and packaging, but I’m not saying that it should. Horse and pig ‘feed’ comes in larger amounts, possibly in bags, whereas dog and cat ‘food’ comes in smaller quantities, in tins. It is odd, but one tends to see the larger amounts as ‘feed’ and the smaller amounts as ‘food’.

On another note, on the horse and pig ‘feed’, it would be strange to see ‘ It does exactly what it says on the bag.’

Ponster

It seems the most normal thing in the world for us to buy food for out pets but this is a recent development. I imagine that up until the 19thC it was normal for dogs/cats to live off scraps and being fed from the dinner table. I doubt that the working class had money to spend specificly on pet food.
Dog food was fist invented in 1860 by a chap named James Spratt, an American living in London. His company produced "Meat Fibrine Dog Cake" and probably would have been referred to as such by shoppers (or they would just have asked for "Spratts"). Cat food first came around in the 1930's.

My guess is that produce such as horse, chicken and general animal feed were rarely purchased by average shoppers, they being mostly linked to farmers or people who owned animals which served a working purpose. When dog food first went on sale it was generally sold in grocers where people bought their regular family food where as horse feed for example was purchased in a different store. Once other brands appeared on the market and people needed a generic name it probably seemed obvious to go with dog food as opposed to feed based on where the product was being sold and that a dog is more often considered a family member who eats "food" rather than a horse or chicken who eats "feed".

p.s. Interesting fact I came across is that a young chap b the name of Charles Cruft worked as General Manager of Spratt's company. He was the founder of "Cruft's dog Show"