@dreaper  
Its seriously a bad thing he isn’t allowed to be truly included with the girls due to not being an Element Bearer there honestly.

Once they got the castle, he actually had a chance to pick out a regular bed for himself. But apparently he likes the baskets, because he’s still sleeping in one.

Its cool, with a 10,000 year life span, Spike will outlive most of them!

Spike is only a slave to the same degree that any child is a slave to their guardian. And less so because Twi is not a strict guardian. As for the basket. It seems likely it simply sprung out of the fact they got him small, and he still is small. If he asked for his own room i hardly think Twilight would be angry.  
Thats said - hes still totally treated like crap for a little brother / friend. But thats mainly because hes ignored and expected to do all Twis mundane work.

you let little boys sleep in your bed?
 
they did have a guest bed…hmmm

Eventually Spike will get so big he’ll miss sleeping in a dog bed.

Spike’s position isn’t nearly as bad as it seems. It only seems bad because of the fact that he is, for all intents and purposes, an oddity. He is the only known Dragon to live in Equestria as a citizen, and experience the pony lifestyle in ways he is able to. The only pony things he misses out on are things that he physically cannot do, but this also exists among the three pony races with one race being able to do something the others cannot.
 
Nonetheless, anypony from the Mane 6 to background ponies speak with him and treat him like any other. And as for ponies treating him like a child, well, he does behave like a child quite often. As smart and mature he may be, he’s still very young, and he acts as such.
 
As for the basket he sleeps in, I’ve never though about it. He seems to like it, possibly a little part of childish ways coming through. I doubt Twilight Sparkle would be upset if he asked for a bigger bed, though.
 
Anyhoo, I’ll leave you with this: If it weren’t for Owloyiscious, Spike would still have been considered Twilight’s familiar, and therefore, her pet. In spite of what had been established with his character in the episodes before Owl’s Well That Ends Well. That episode was the final nail to the idea of Spike being a pet, and to think otherwise is foolish, especially since Twilight let Spike leave on his own long journey in Dragon Quest. Granted, they followed him, but Twilight, Dash and Rarity didn’t reveal themselves until Spike genuinely needed backup.

If you overanalyze My Little Pony, you’re gonna have a bad time.

What if Spike, like, has a thing for doggy beds?

Nah dude, you got it all backwards. Dragons love to sleep curled up around things, but inside something is still good.

Twilight is a wizard and Spike is her familiar.

But hey, Spike DID get TWO episodes specifically dedicated to him. TWO episodes. That MUST mean SOMETHING, right?

@unknown: I always assumed that they get paid for it, which would be the reason why the farm at Sweet Apple Acres only has the family working there.
 
Besides, we’ve seen cows walk around town shopping for stuff.

i think that keeping sentient cows in pens that you herded (basically forced) them into is much closer to slavery than this.

@ClownDicks: Yes.
 
@dreaper: Tep, that’s more or less the jist of it. He’s quite literally the little brother of the group.

I’m just going to paste what I posted in another forum:
 
Spike is not treated as a slave, he would be treated far, far worse if that were the case and it would be far too noticeable in the show. I mean, you got this series about love and friendship but you got this character that gets treated like crap all the time, that would be hypocritical of the show if that happened. Also the ponies have shown that they care about him several times in past episodes.
 
However, Spike’s position right now is not good either. He is basically the “extra” friend of the mane 6, he is their friend but doesn’t fully belong to them and thats because of the following:
 

@Glitch  
My post or his?

@ClownDicks: There’s no way that this was typed without a troll face.

It’s funny, because it’s all true.

>Spike works his ass off.
 
That’s implying that no one else does.
 
>is treated as a lesser citizen
 
When? I think you’re projecting a bit.
 
>isn’t paid for his services
 
Those are called chores. Beside, how do we know he doesn’t get paid? He knows the princess personally, do you really think he wouldn’t have an allowance?
 
No, he’s not a slave.

Oh great, it’s one of these…

Hey this like one of those ponyconfession things.

SPIKE IS TWILIGHT’S FIRST PET.