Barb thanks for doing this. My 2 cents is to make OTHER shelters to put out - this gives cats a choice of where to go, and if tom is taking the heated house, gives them OPTIONS. V. important to remember cats like variety!
Here's what I'd do - make a couple of cheap and sturdy rubbermaid shelters - I made 6 for my 15 ferals. - couple of those are toms that are aggressive and chase out toher cats - this way, the ALL have shelters - so they can go to another one if they've been chased away or out of another one.
Make about 3 of these shelters - rubbermaid containers can be bought cheaply = 5 dollars or so for a 30 gallon or bigger. Line it with 3 inches of newspapers or put (kf you can) some bubble wrap insulation of the type ysed to wrap pipe and heaters... then put in straw NOT hay. if you can find it, I found mine at craft stores, LOL. but farmers will often give you some in loose garbage bags you need about 1 bag of straw for 3 of these shelters.
Cut a hole ysing a saw - my BF did this for me - use a coffee can to
mark hole then cut
I made one hole and mine seem happy but if you need to , you can do 2 holes one on each end of container.
Stuff w/ straw, put lid on! Et volia instand warm
dry shelter. Now, a second step - get a card table weigh it down with cinder block or brick or even in a pinch bundled old telephone books ... put a tarp
over the table, draped with a hole on one side, so the cats can go under (or on top if they like, LOL) Put the containers under there... They will stay warm dry and sheltered from winds and damp. And if the tom chases them,
they have alternate places -
if possible make this arrangement near by the deck they hid under - so if chased out of the shelters they can run deck easily.
Also, if it were me? I'd Trap the the Tom cat, and get him neutered. It may reduce agression in the tom, and would help with smell. Also, it will stop any kittens that are unwanted from being born.
If tom is someone's cat, put a collar on it with a note "I eat @ name/phone number" who am I? This will alert owner cat is being a nusiance. perhaps owner would then keep in at night, so your cats could shelter during coldest
part of the night uninterrupted.
Hopes this helps!