Your photos have just been sent on to me and I can now see exactly what you have.
This is a beautiful set of old Dedham pottery plates dating to the Hugh Robertson era, circa 1896 - 1928, when the mark was a square blue stamp with DEDHAM POTTERY above a rabbit, sometimes accompanied with a foreshortened rabbit stamp impressed into the clay (no ink).
This older Dedham production is becoming more and more hard to find and prices for it continue to be as good as ever.
Here are the value ranges of each if you were to sell at a good antique auction or on line (eBay etc):
1 Magnolia pattern dinner plate.........120 - 180
1 Turkey pattern dinner plate............250 - 375
4 duck pattern dinner plates...........640 - 960 (for all)
Total................................circa $1000 - $1500.
Therefore your set has a full retail value (if you saw it for sale in an antique store) of $3000. This is also the replacement value for insurance purposes.
I do hope this helps!
Please let me know if you'd like me to explain or expand on any of the above, I would be glad to.