I agree with Aly. Leaving a dog tied up can be very dangerous also. My friend's german shepard almost lost her paw because the tie-out became wrapped around it.

Please describe this "shed." Is there windows? How big is it? A dog run with an igloo/dog house and a cover would be much better than a shed...I imagine it has poor ventilation.

Do you keep the dogs groomed? Grooming could really help your step-dad's allergies to them. If you bath them often and brush them, they won't shed so much. You can buy a special shedding spray too. Also take them to a groomer and have them shave them completely down....back and legs (well, only do this if you could let them in the house again).

Please....if your dogs have to live like that...in a shed..consider finding them a new home. And do not get the mastiff in their place! Would the mastiff have to live in the shed? How do you know your step-dad would not be allergic to that dog too?