Certified GKH Gardening Expert
If these were kept from a previous year's seed, then this will be why. Essentially, it is not the same squash as the parent. This is common when planting from open pollinated seeds, as there are many types of squash that can cross pollinate. You may get quite a bit of variability from the same plant.
You can still use them.
Here is an article that will help you to care for squash: