In the letter (#200) to Carl Swanson, written circa March 1932, we can learn:

Dear Mr. Swanson: 
I am sending you, under separate cover, a manuscript entitled “The Hoofed Thing” which I hope you can use in your magazine. I am sending this at a venture, as I have not been able to secure a copy of your publication, and so don’t know just what type of stories you use.

And again in a letter (#201) to Swanson, circa April:

If you like “The Hoofed Thing”, use it, and pay me whatever you are able. Also please keep the $.25 I sent you, and send me a copy of your magazine as soon as it is published — also let me know what the subscription price is.

Further information can be read in a letter (#203) to H.P. Lovecraft, ca. April 1932:

Swanson’s venture seems rather amateurish, but he may make something of it. I let him have a yarn, “The Hoofed Thing” which Bates had previously rejected.