Conclusion

The eggs that held the most weight before cracking were caged eggs.  The eggs that held the least weight before cracking were caged eggs.  The eggs that held the most weight before breaking were free range eggs.  The eggs that broke with the least amount of weight were free range eggs.

Since there was no clear difference in the strength of the eggs my hypothesis may be wrong.  It is also possible that the results are not accurate because I did this experiment in winter and the free range hens may not have been outside much and they may have had the same food as caged hens.  However the yolks of the free range eggs were darker in colour than the yolks of the caged hens so it looks as though they had different food.

I may try this experiment again in late spring or I may do other experiments to see whether small eggs are stronger than large eggs and whether white eggs are stronger than brown.