The entire family is going to WDW in April to celebrate my niece's first birthday at the Poly. We have reserved a crib for the room. However, can you reserve or get a high chair for the room too? Has anybody done this? Thanks.

I've never heard of it, but that doesn't mean it's not possible. BUT, high chairs are normally associated with eating a meal, and Disney assumes eating of meals is generally done in restaurants, not your room, so I would be surprised if this was an option. I'd recommend calling the Poly directly. There's a phone number on the Poly page of MousePlanet that I'd try.

Now it has been a while since I needed a high chair, but if I remember correctly, they do not offer them for in room use.

There are off-site rental agencies (A baby's best friend is one) where you can get one for your stay.

I haven't been to this resort, but we used a booster seat or portable plastic chair when we took our toddlers with us to a hotel/motel. Some of the plastic chairs come with a snap-on tray too. Worked very well for us.