Do Fireplaces and Cooking Hearths count as a Bake Bread Action Space?
During the Work Phase your family members perform Actions that are selected from those currently available on the board.

Stage 1 has the Sow and/or Bake Bread Action which will show up sometime during the first four rounds (Other bake actions are also available depending on how many players there are). To use the Bake Bread part of this action you must have an Improvement that bakes the Bread like the Fireplace, Cooking Hearth or an Oven.

These Improvements are not Action Spaces themselves, they are just the tools you will use to make your Actions more efficient. You will put your worker on the Action space that bakes bread, then use an improvement to determine the outcome of the baking action. You may use every baking improvement you have as many times as it allows per Bake Bread action.

Note that the fireplaces and hearths can convert multiple grain while the ovens are limited to 1 or 2. The Clay Oven and Stone Oven, and some others like the Baker's Oven, allow you to Bake Bread immediately when they are purchased. Some Improvements, like the Windmill, allow you to convert grain to (more than one) food at any time without using a Bake action.