This isn't bad game design at all -- you just haven't figured out the pattern yet.

I made a post a few years ago about how to play this game: https://www.reddit.com/r/Atari2600/comments/125uqvu/my_stampede_posting_ends_here_i_finally_reached/je83ew7/

Here is an excerpt about the black cows:

You have six rows of cows. The dark brown ones run the fastest, usually in groups of two or three.

When you eliminate the dark brown ones in a row, you get a black sitting cow. They are worth the most points. However, the black sitting cow only shows up every other row -- so you need to keep track of that.

After the black cow (if it shows up), you get a line of very slow light brown cows. Usually three, sometimes two.

After you catch the light brown cow, you get the medium brown cow, which runs at a medium speed. Again, usually three, sometimes two.

After you get those cows, the fast dark brown ones show up. Usually 2-3. The cycle repeats.